Build/Test Tools: Update several dependencies.

This updates the following dependencies:

- `cssnano` from version `4.1.10` to `4.1.11`.
- `grunt-webpack` from `4.0.2` to `4.0.3`.
- `qunit` from `12.14.1` to `12.15.0`.
- `sass` from `1.32.8` to `1.32.11`.
- `uglify-js` from `3.13.3` to `3.13.4`.

See #52624.
Built from https://develop.svn.wordpress.org/trunk@50774


git-svn-id: http://core.svn.wordpress.org/trunk@50383 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.8-alpha-50773';
+$wp_version = '5.8-alpha-50774';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.