Update GitHub Actions for Laravel 9

Author: laravel-shift

.github/workflows/tests.yml

@@ -17,7 +17,7 @@ jobs:
 
     strategy:
       matrix:
-        php: [7.3, 7.4, 8.0]
+        php: [7.3, 7.4, 8.0, 8.0]
         stability: [prefer-lowest, prefer-stable]
 
     # Steps represent a sequence of tasks that will be executed as part of the job