Ignore non-php8 compatible Laravel versions for tests

Author: mpociot

.github/workflows/ci.yml

@@ -36,6 +36,11 @@ jobs:
             testbench: '5.*'
           - laravel: '8.*'
             testbench: '6.*'
+        exclude:
+          - php: '8.0'
+            laravel: 6.*
+          - php: '8.0'
+            laravel: 7.*
 
     name: PHP ${{ matrix.php }} - Laravel ${{ matrix.laravel }} --${{ matrix.prefer }}