Add PHP 8 in the test matrix

Author: manavo

.github/workflows/tests.yml

@@ -10,7 +10,7 @@ jobs:
         strategy:
             fail-fast: false
             matrix:
-                php: [8.2, 8.1]
+                php: [8.2, 8.1, 8.0]
                 laravel: [10.*, 9.*, 8.*]
                 dependency-version: [prefer-lowest, prefer-stable]
                 include: