Correct the github workflows

Author: ingeniumed

.github/workflows/phpcs.yml

@@ -13,7 +13,7 @@ jobs:
     strategy:
       matrix:
         php-versions:
-          - 8.0
+          - 8.1
 
     steps:
       - uses: actions/checkout@v2

.github/workflows/phpunit.yml

@@ -18,11 +18,11 @@ jobs:
       matrix:
         include:
           # Check lowest supported WP version, with the lowest supported PHP.
-          - php: "8.0"
+          - php: "8.1"
             wp: "6.0"
             allowed_failure: false
           # Check latest WP with the lowest supported PHP.
-          - php: "8.0"
+          - php: "8.1"
             wp: "master"
             allowed_failure: false
           # Check latest WP with the highest supported PHP.