laravel 8 support

Author: timoladoyinbo

.github/workflows/run-tests.yml

@@ -10,7 +10,7 @@ jobs:
       matrix:
         os: [ubuntu-latest, windows-latest]
         php: [7.4]
-        laravel: [7.*]
+        laravel: [8.*, 7.*]
         dependency-version: [prefer-lowest, prefer-stable]
         include:
           - laravel: 8.*