Update gulpfile and README for gulp 4.x

Fixes for these gulp errors:
  - AssertionError [ERR_ASSERTION]: Task function must be specified
  - AssertionError [ERR_ASSERTION]: Task never defined: readme
  -   gulpjs/gulp#802
  - The following tasks did not complete: check-priv
    - Did you forget to signal async completion?
  - Error: watching conf.priv.js,completions.js,conf.js,actions.js,help.js,keys.js,util.js,gulpfile.js: watch task has to be a function (optionally generated by using gulp.parallel or gulp.series)

Update README to use local ./node_modules/.bin/gulp instead of global
gulp.

README.md

@@ -238,7 +238,7 @@ Building `surfingkeys-conf` requires a few dependencies to be installed:
 
 4. __Gulp Build/Install__
  ```shell
- $ gulp install # OR "gulp build" to build to ./build/.surfingkeys without installing
+ $ ./node_modules/.bin/gulp install # OR "./node_modules/.bin/gulp build" to build to ./build/.surfingkeys without installing
  ```
 
  This will build the final configuration file and place it at `~/.surfingkeys`.
@@ -260,14 +260,14 @@ Building `surfingkeys-conf` requires a few dependencies to be installed:
   - __Linux__: `file:///home/{USERNAME}/.surfingkeys` (replace `{USERNAME}` with your username) 
   - __macOS__: `file:///Users/{USERNAME}/.surfingkeys` (replace `{USERNAME}` with your username) 
   - __Windows__: `file://%Homedrive%%Homepath%/.surfingkeys` (This is a guess, please correct me if I'm wrong)
- - __IV.__ Hack Away! If you ever make a change to any of your configuration files in the future, simply run `gulp install` again and your new configuration will automatically be loaded by SurfingKeys.
+ - __IV.__ Hack Away! If you ever make a change to any of your configuration files in the future, simply run `./node_modules/.bin/gulp install` again and your new configuration will automatically be loaded by SurfingKeys.
 
  </details>
 
  <details>
  <summary><strong>Option B</strong>: Manually copy/paste into the SurfingKeys configuration form</summary>
 
- - __I.__ Copy the contents of `./build/.surfingkeys` (or `$HOME/.surfingkeys` if you ran `gulp install`)
+ - __I.__ Copy the contents of `./build/.surfingkeys` (or `$HOME/.surfingkeys` if you ran `./node_modules/.bin/gulp install`)
 
  - __II.__ Open the SurfingKeys [configuration page](chrome-extension://mffcegbjcdejldmihkogmcnkgbbhioid/pages/options.html)
 

README.tmpl.md

@@ -93,7 +93,7 @@ Building `surfingkeys-conf` requires a few dependencies to be installed:
 
 4. __Gulp Build/Install__
  ```shell
- $ gulp install # OR "gulp build" to build to ./build/.surfingkeys without installing
+ $ ./node_modules/.bin/gulp install # OR "./node_modules/.bin/gulp build" to build to ./build/.surfingkeys without installing
  ```
 
  This will build the final configuration file and place it at `~/.surfingkeys`.
@@ -115,14 +115,14 @@ Building `surfingkeys-conf` requires a few dependencies to be installed:
   - __Linux__: `file:///home/{USERNAME}/.surfingkeys` (replace `{USERNAME}` with your username) 
   - __macOS__: `file:///Users/{USERNAME}/.surfingkeys` (replace `{USERNAME}` with your username) 
   - __Windows__: `file://%Homedrive%%Homepath%/.surfingkeys` (This is a guess, please correct me if I'm wrong)
- - __IV.__ Hack Away! If you ever make a change to any of your configuration files in the future, simply run `gulp install` again and your new configuration will automatically be loaded by SurfingKeys.
+ - __IV.__ Hack Away! If you ever make a change to any of your configuration files in the future, simply run `./node_modules/.bin/gulp install` again and your new configuration will automatically be loaded by SurfingKeys.
 
  </details>
 
  <details>
  <summary><strong>Option B</strong>: Manually copy/paste into the SurfingKeys configuration form</summary>
 
- - __I.__ Copy the contents of `./build/.surfingkeys` (or `$HOME/.surfingkeys` if you ran `gulp install`)
+ - __I.__ Copy the contents of `./build/.surfingkeys` (or `$HOME/.surfingkeys` if you ran `./node_modules/.bin/gulp install`)
 
  - __II.__ Open the SurfingKeys [configuration page](chrome-extension://mffcegbjcdejldmihkogmcnkgbbhioid/pages/options.html)
 

gulpfile.js

@@ -37,7 +37,7 @@ gulp.task("gulp-autoreload", () => {
  let p
  const spawnChildren = function spawnChildren() {
  if (p) p.kill()
- p = spawn("gulp", ["lint-gulpfile", "install", "watch-nogulpfile"], { stdio: "inherit" })
+ p = spawn("./node_modules/.bin/gulp", ["lint-gulpfile", "install", "watch-nogulpfile"], { stdio: "inherit" })
  }
  gulp.watch("gulpfile.js", spawnChildren)
  spawnChildren()
@@ -57,32 +57,16 @@ gulp.task("lint", () =>
  .pipe(eslint())
  .pipe(eslint.format()))
 
-gulp.task("check-priv", () => {
+gulp.task("check-priv", (done) => {
  try {
  fs.statSync("./conf.priv.js")
  } catch (e) {
  // eslint-disable-next-line no-console
  console.log("Creating ./conf.priv.js based on ./conf.priv.example.js")
  fs.copyFileSync("./conf.priv.example.js", "./conf.priv.js", fs.constants.COPYFILE_EXCL)
  }
-})
-
-gulp.task("build", ["check-priv", "clean", "lint", "readme"], () => gulp.src(paths.entry, { read: false })
- .pipe(parcel())
- .pipe(rename(".surfingkeys"))
- .pipe(gulp.dest("build")))
-
-gulp.task("install", ["build"], () => gulp.src("build/.surfingkeys")
- .pipe(gulp.dest(os.homedir())))
-
-gulp.task("watch", () => {
- gulp.watch([].concat(paths.scripts, paths.gulpfile), ["readme", "install"])
- gulp.watch(paths.readme, ["readme"])
-})
 
-gulp.task("watch-nogulpfile", () => {
- gulp.watch([].concat(paths.scripts), ["readme", "install"])
- gulp.watch(paths.readme, ["readme"])
+ done()
 })
 
 gulp.task("readme", () => {
@@ -154,4 +138,26 @@ gulp.task("readme", () => {
  .pipe(gulp.dest("."))
 })
 
-gulp.task("default", ["build"])
+gulp.task("build", gulp.series("check-priv", "clean", "lint", "readme"), (done) => {
+ gulp.src(paths.entry, { read: false })
+ .pipe(parcel())
+ .pipe(rename(".surfingkeys"))
+ .pipe(gulp.dest("build"))
+
+ done()
+})
+
+gulp.task("install", gulp.series("build"), () => gulp.src("build/.surfingkeys")
+ .pipe(gulp.dest(os.homedir())))
+
+gulp.task("watch", () => {
+ gulp.watch([].concat(paths.scripts, paths.gulpfile), gulp.series("readme", "install"))
+ gulp.watch(paths.readme, gulp.series("readme"))
+})
+
+gulp.task("watch-nogulpfile", () => {
+ gulp.watch([].concat(paths.scripts), gulp.series("readme", "install"))
+ gulp.watch(paths.readme, gulp.series("readme"))
+})
+
+gulp.task("default", gulp.series("build"))