fix: remove PHP 8.1 from workflow matrix to align with project requirements

Author: frknasir

.github/workflows/tests.yml

@@ -14,7 +14,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest]
-        php: [8.1, 8.2, 8.3]
+        php: [8.2, 8.3]
         stability: [prefer-lowest, prefer-stable]
 
     name: P${{ matrix.php }} - ${{ matrix.stability }} - ${{ matrix.os }}