chore: add laravel 12 to test matrix (2)

Author: tpetry

.github/workflows/unit-tests.yml

@@ -19,7 +19,7 @@ jobs:
       fail-fast: false
       matrix:
         php: [8.0, 8.1, 8.2, 8.3]
-        laravel: [6.*, 7.*, 8.*, 9.*, 10.*, 11.*]
+        laravel: [6.*, 7.*, 8.*, 9.*, 10.*, 11.*, 12.*]
         stability: [prefer-lowest, prefer-stable]
         exclude:
           # These combinations should work, but there is a problem when testing...