Add Laravel 12 to testing matrix

Author: duncanmcclean

.github/workflows/tests.yml

@@ -13,7 +13,7 @@ jobs:
     strategy:
       matrix:
         php: [8.2, 8.3, 8.4]
-        laravel: [10.*, 11.*]
+        laravel: [10.*, 11.*, 12.*]
         stability: [prefer-lowest, prefer-stable]
         os: [ubuntu-latest]
         exclude: