Use fs.rm() instead of rimraf

A regression occurred in 0.2.2 which can be reproduced using:

```js
const assert = require('assert');
const tmp = require('tmp');
tmp.dir({ unsafeCleanup: true }, (err, path, cleanup) => {
  assert.ifError(err);
  cleanup(assert.ifError);
});
```
This works with 0.2.1.  With 0.2.2 it fails with:

    /path/to/tmp/node-tmp/lib/tmp.js:358
            return removeFunction(fileOrDirName, next || function() {});
                   ^

    TypeError: removeFunction is not a function
        at _cleanupCallback (/path/to/tmp/node-tmp/lib/tmp.js:358:16)
        at /path/to/tmp/node-tmp/repro.js:5:3
        at _dirCreated (/path/to/tmp/node-tmp/lib/tmp.js:207:7)
        at FSReqCallback.oncomplete (node:fs:192:23)

This occurs because 00bb5b2 upgraded
the rimraf dependency from ^3.0.0 to ^5.0.5 without handling the change
to a `Promise`-based API in 4.0.0
(isaacs/rimraf@a71e7f9)
or the removal of the default export in 5.0.0
(isaacs/rimraf@c7a3fd4).

This commit fixes the issue by dropping the `rimraf` dependency in favor
of `fs.rm({recursive: true})`.

Fixes: 00bb5b2 ("Update rimraf and drop old Node compatibility")
Fixes: #295
Signed-off-by: Kevin Locke <kevin@kevinlocke.name>

lib/tmp.js

@@ -14,7 +14,6 @@ const os = require('os');
 const path = require('path');
 const crypto = require('crypto');
 const _c = { fs: fs.constants, os: os.constants };
-const rimraf = require('rimraf');
 
 /*
  * The working inner variables.
@@ -43,12 +42,42 @@ const
   _removeObjects = [],
 
   // API change in fs.rmdirSync leads to error when passing in a second parameter, e.g. the callback
-  FN_RMDIR_SYNC = fs.rmdirSync.bind(fs),
-  FN_RIMRAF_SYNC = rimraf.sync;
+  FN_RMDIR_SYNC = fs.rmdirSync.bind(fs);
 
 let
   _gracefulCleanup = false;
 
+/**
+ * Recursively remove a directory and its contents.
+ *
+ * @param {string} dirPath path of directory to remove
+ * @param {Function} callback
+ */
+function rimraf(dirPath, callback) {
+  // fs.rm() was added in Node.js 14.14.
+  // Use deprecated rmdir({recursive: true}) on older versions.
+  if (!fs.rm) {
+    return fs.rmdir(dirPath, { recursive: true }, callback);
+  }
+
+  return fs.rm(dirPath, { recursive: true }, callback);
+}
+
+/**
+ * Recursively remove a directory and its contents, synchronously.
+ *
+ * @param {string} dirPath path of directory to remove
+ */
+function FN_RIMRAF_SYNC(dirPath) {
+  // fs.rm() was added in Node.js 14.14.
+  // Use deprecated rmdir({recursive: true}) on older versions.
+  if (!fs.rm) {
+    return fs.rmdirSync(dirPath, { recursive: true });
+  }
+
+  return fs.rmSync(dirPath, { recursive: true });
+}
+
 /**
  * Gets a temporary file name.
  *

package.json

@@ -25,7 +25,6 @@
     "node": ">=14"
   },
   "dependencies": {
-    "rimraf": "^5.0.5"
   },
   "devDependencies": {
     "eslint": "^6.3.0",