Add PHP 8.1 to the CI matrix (#66)

Author: dunglas

.github/workflows/static-analysis.yml

@@ -15,7 +15,7 @@ jobs:
       - name: "installing PHP"
         uses: "shivammathur/setup-php@v2"
         with:
-          php-version: "8.0"
+          php-version: "8.1"
           ini-values: memory_limit=-1
           tools: composer:v2, phpstan, cs2pr
 

.github/workflows/unit-tests.yml

@@ -23,6 +23,7 @@ jobs:
           - "7.3"
           - "7.4"
           - "8.0"
+          - "8.1"
         operating-system:
           - "ubuntu-latest"