Build/Test Tools: Update several NPM packages.

This updates the following packages to the latest versions. 

Updated packages:
- `copy-webpack-plugin` from `5.1.1` to `5.1.2`.
- `grunt` from `1.1.0` to `1.3.0`.
- `grunt-contrib-jshint` from `2.1.0` to `3.0.0`.
- `grunt-contrib-qunit` from `3.1.0` to `4.0.0`.
- `grunt-rtlcss` from `2.0.1` to `2.0.2`.
- `qunit` from `2.9.0` to `2.13.0`.
- `sinon` from `9.0.0` to `9.2.2`.
- `source-map-loader` from `0.2.4` to `1.1.3`.
- `uuid` from `8.2.0` to `8.3.2`.
- `webpack-dev-server` from `3.11.0` to `3.11.1`.

See #51801.
Built from https://develop.svn.wordpress.org/trunk@49939


git-svn-id: http://core.svn.wordpress.org/trunk@49638 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/css/common-rtl.css

@@ -2535,7 +2535,7 @@ div.star-holder .star-rating {
 }
 
 .rtl .star-rating .star-half {
-	transform: rotateY(180deg);
+	transform: rotateY(-180deg);
 }
 
 .star-rating .star-empty:before {

wp-includes/js/dist/blocks.js

@@ -5467,6 +5467,7 @@ if (true) {
 
 
 
+
 /***/ }),
 
 /***/ 29:

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.7-alpha-49938';
+$wp_version = '5.7-alpha-49939';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.