ci: Update GH action to use actions/cache v3

Author: courtney-miles

.github/workflows/tests.yml

@@ -32,7 +32,7 @@ jobs:
 
             - name: Cache Composer packages
               id: composer-cache
-              uses: actions/cache@v2
+              uses: actions/cache@v3
               with:
                   path: vendor
                   key: ${{ runner.os }}-php-${{ hashFiles('**/composer.lock') }}