fix: build os version

.github/workflows/php.yml

@@ -16,7 +16,7 @@ jobs:
   build:
 
     # Only ubuntu 16.04 has 5.6 and 7.0 preinstalled
-    runs-on: ubuntu-16.04
+    runs-on: ubuntu-latest
     strategy:
       max-parallel: 1
       matrix:
@@ -25,13 +25,13 @@ jobs:
     steps:
     - name: Checkout
       uses: actions/checkout@v2
-    
+
     - name: Setup PHP Action
       uses: shivammathur/[email protected]
       with:
           php-version: ${{ matrix.php-versions }}
           coverage: xdebug
-          
+
     - name: Validate composer.json and composer.lock
       run: composer validate --no-check-lock
     - name: Get composer cache directory