chore: add PHP 8.1 (#1039)

Author: bshaffer

.github/workflows/tests.yml

@@ -35,7 +35,7 @@ jobs:
         options: --health-cmd="pg_isready -h localhost" --health-interval=10s --health-timeout=5s --health-retries=5
     strategy:
       matrix:
-        php: [ 7.1, 7.2, 7.3, 7.4, "8.0", 8.1 ]
+        php: [ 7.1, 7.2, 7.3, 7.4, "8.0", 8.1, 8.2 ]
     name: "PHP ${{ matrix.php }} Unit Test"
     steps:
       - uses: actions/checkout@v2