Update master php testing versions

Signed-off-by: Joas Schilling <coding@schilljs.com>

Author: nickvergessen

.github/workflows/lint-php.yml

@@ -18,7 +18,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        php-versions: ["7.4", "8.0"]
+        php-versions: ["7.3", "7.4", "8.0", "8.1"]
 
     name: php-lint
 

.github/workflows/test.yml

@@ -60,7 +60,7 @@ jobs:
 
     strategy:
       matrix:
-        php-version: [ 7.4, 8.0 ]
+        php-version: [ "7.4", "8.0", "8.1" ]
         nextcloud-version: [ 'master', 'stable21' ]
         browser: [ 'firefox', 'chrome' ]
         db: [ 'mysql' ]