ci: update deprecated GitHub Actions to v4

Author: jasonbahl

.github/workflows/tests-wordpress.yml

@@ -31,7 +31,7 @@ jobs:
             wordpress: '6.2'
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
 
       - name: Build container image
         env:
@@ -51,10 +51,10 @@ jobs:
 
       - name: Get Composer Cache Directory
         id: composercache
-        run: echo "::set-output name=dir::$(composer config cache-files-dir)"
+        run: echo "dir=$(composer config cache-files-dir)" >> $GITHUB_OUTPUT
 
       - name: Cache dependencies
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: ${{ steps.composercache.outputs.dir }}
           key: php-${{ matrix.php }}-${{ runner.os }}-composer-${{ hashFiles('**/composer.lock') }}