fix: skip following argument when current argument is --app

dokku

@@ -35,10 +35,12 @@ source "$PLUGIN_CORE_AVAILABLE_PATH/common/functions"
 
 parse_args "$@"
 args=("$@")
+skip_arg=false
 if [[ "${args[0]}" =~ ^--.* ]]; then
   for arg in "$@"; do
+    $skip_arg && skip_arg=false && continue
     if [[ "$arg" == "--app" ]]; then
-      shift 2
+      shift 2 && skip_arg=true
     elif [[ "$arg" =~ ^--.* ]]; then
       shift 1
     else