new: [mariadb] support debian 11 and debian 12 installation

mariadb/hooks/install.d/60-backup.sh

@@ -24,7 +24,7 @@ type -p mysql >/dev/null || {
     case $(lsb_release -is) in
         Debian)
             case $(lsb_release -rs) in
-                10)
+                10|11|12)
                     apt-get install -y default-mysql-client </dev/null
                     ;;
                 *)
@@ -35,7 +35,10 @@ type -p mysql >/dev/null || {
         Ubuntu)
             apt-get install -y mysql-client </dev/null
             ;;
-    esac
+    esac || {
+        echo "Error: could not install mysql client" >&2
+        exit 1
+    }
 }
 
 if ! [ -e "/root/.my.cnf" ]; then