add testing for mysql-server/customer-update of allowed_mysqlserver; beautify config-command/file details

Signed-off-by: Michael Kaufmann <d00p@froxlor.org>

.github/workflows/build-mysql.yml

@@ -8,7 +8,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php-versions: ['7.4', '8.0']
+        php-versions: ['7.4', '8.1']
         mysql-version: [8.0, 5.7]
     steps:
       - name: Checkout