use php 8.3 stable

Author: Kanti

.github/workflows/run-grumphp-test.yml

@@ -6,7 +6,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php: ['8.1', '8.2', '8.3-rc']
+        php: ['8.1', '8.2', '8.3']
     container:
       image: kanti/buildy:${{ matrix.php }}
     steps: