feat: added multi preload scripts support as per #118

preload script scope should be determined as such:
preload.scope.ts

package.json

@@ -13,7 +13,7 @@
  "test": "jest --maxWorkers=1 .*.spec.ts",
  "compile": "tsc",
  "build": "npm run clear:all && tsc && npm run copy:all && npm run permission",
- "publish": "cd build && npm publish",
+ "publish": "npm publish build",
  "release": "standard-version",
  "postrelease": "git push --follow-tags && npm run build && npm run publish",
  "permission": "node ./scripts/make_build_public.js",

src/builders/package/package.impl.ts

@@ -138,7 +138,7 @@ function _createBaseConfig(options: PackageElectronBuilderOptions, context: Buil
  {
  from: resolve(options.sourcePath, options.name),
  to: options.name,
- filter: ['main.js', 'preload.js', 'assets']
+ filter: ['main.js', 'preload.(.+\.)?js', 'assets']
  },
  {
  from: resolve(options.sourcePath, options.name),