ci: update PHPCS dev branch from master to 3.x

The PHPCS repository moved from squizlabs to phpcsstandards
and no longer has a master branch. The dev CI jobs need to
track the 3.x branch until WPCS (and by extension VIPCS)
is compatible with PHPCS 4.x.

Author: GaryJones

.github/workflows/basics.yml

@@ -42,8 +42,8 @@ jobs:
         run: composer validate --no-check-all --strict
 
       - name: 'Composer: adjust dependencies'
-        # Using PHPCS `master` as an early detection system for bugs upstream.
-        run: composer require --no-update --no-scripts squizlabs/php_codesniffer:"dev-master" --no-interaction
+        # Using PHPCS `3.x` as an early detection system for bugs upstream.
+        run: composer require --no-update --no-scripts squizlabs/php_codesniffer:"3.x-dev" --no-interaction
 
       # Install dependencies and handle caching in one go.
       # @link https://github.com/marketplace/actions/install-php-dependencies-with-composer

.github/workflows/test.yml

@@ -117,7 +117,7 @@ jobs:
         if: ${{ matrix.dependencies == 'dev' }}
         run: >
           composer require --no-update --no-scripts --no-interaction
-          squizlabs/php_codesniffer:"dev-master"
+          squizlabs/php_codesniffer:"3.x-dev"
           phpcsstandards/phpcsutils:"dev-develop"
           phpcsstandards/phpcsextra:"dev-develop"
           sirbrillig/phpcs-variable-analysis:"2.x"