chore(github): Update Github Actions deprecations

Author: klausi

.github/workflows/testing.yml

@@ -15,7 +15,7 @@ jobs:
             phpstan: '1'
     steps:
       - name: Checkout Coder
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
       - name: Setup PHP, with composer and extensions
         uses: shivammathur/setup-php@v2
         with:
@@ -25,9 +25,9 @@ jobs:
           coverage: none
       - 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 composer dependencies
-        uses: actions/cache@v2
+        uses: actions/cache@v3
         with:
           path: ${{ steps.composercache.outputs.dir }}
           # Use composer.json for key, if composer.lock is not committed.