add Laravel 9 to testing matrix

Author: lupinitylabs

.github/workflows/tests.yml

@@ -15,7 +15,7 @@ jobs:
             fail-fast: true
             matrix:
                 php: [ 7.3, 7.4, 8.0, 8.1 ]
-                laravel: [ 7.*, 8.* ]
+                laravel: [ 7.*, 8.*, 9.* ]
                 dependency-version: [ prefer-stable ]
                 exclude:
                     -   php: 8.1