Update run-tests.yml

Update cache action to v4

Author: bpedroza

.github/workflows/run-tests.yml

@@ -24,7 +24,7 @@ jobs:
 
     - name: Cache Composer packages
       id: composer-cache
-      uses: actions/cache@v2
+      uses: actions/cache@v4
       with:
         path: vendor
         key: ${{ runner.os }}-php-${{ hashFiles('**/composer.lock') }}