test(php): Enable PHP 8.3 testing

.github/workflows/testing.yml

@@ -7,16 +7,16 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php-versions: ['7.2', '7.3', '7.4', '8.0', '8.1']
+        php-versions: ['7.2', '7.3', '7.4', '8.0', '8.1', '8.2']
         extra-tests: ['0']
         # We only need to run PHPStan and Druapl core regression tests once on
         # the latest PHP version.
         include:
-          - php-versions: '8.2'
+          - php-versions: '8.3'
             extra-tests: '1'
     steps:
       - name: Checkout Coder
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Setup PHP, with composer and extensions
         uses: shivammathur/setup-php@v2
@@ -31,7 +31,7 @@ jobs:
         run: echo "dir=$(composer config cache-files-dir)" >> $GITHUB_OUTPUT
 
       - name: Cache composer dependencies
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: ${{ steps.composercache.outputs.dir }}
           # Use composer.json for key, if composer.lock is not committed.
@@ -72,10 +72,8 @@ jobs:
 
       - name: Run PHPCS on Drupal core for regressions
         if: ${{ matrix.extra-tests == '1' }}
-        # @todo Remove the ignored files once Drupal core has fixed them.
-        # In case more Drupal core files have known problems that should be
-        # ignored, add them with the --ignore option.
+        # In case Drupal core files have known problems that should be
+        # ignored temporarily, add them with the --ignore option.
         run: |
           cd drupal/core
-          ../../vendor/bin/phpcs -p \
-            --ignore=modules/sdc/src/ExtensionType.php,lib/Drupal/Core/Database/Transaction/ClientConnectionTransactionState.php,lib/Drupal/Core/Database/Transaction/StackItemType.php
+          ../../vendor/bin/phpcs -p