ci: downgrade GitHub runner image for Behat tests

Author: stklcode

.github/workflows/tests.yml

@@ -27,7 +27,7 @@ jobs:
         composer install
         ./vendor/bin/phpunit -c ./phpunit.xml.dist
   behat:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     services:
       mysql:
         image: mysql:5.7