Run tests on PHP 8.1

Signed-off-by: Alexander M. Turek <[email protected]>

Author: derrabus

.github/workflows/ci.yaml

@@ -11,7 +11,7 @@ jobs:
         strategy:
             fail-fast: false
             matrix:
-                php: [ '7.2', '7.3', '7.4', '8.0' ]
+                php: [ '7.2', '7.3', '7.4', '8.0', '8.1' ]
                 monolog: [ '1.*', '2.*' ]
                 include:
                     -   php: '7.1'