Replace argument assignation with signatures on MemoryLimit

Reference: https://progress.opensuse.org/issues/178948

Author: Wabri

lib/OpenQA/WebAPI/Plugin/MemoryLimit.pm

@@ -2,15 +2,13 @@
 # SPDX-License-Identifier: GPL-2.0-or-later
 
 package OpenQA::WebAPI::Plugin::MemoryLimit;
-use Mojo::Base 'Mojolicious::Plugin';
+use Mojo::Base 'Mojolicious::Plugin', -signatures;
 
 use BSD::Resource 'getrusage';
 use Mojo::IOLoop;
 
 # Stop prefork workers gracefully once they reach a certain size
-sub register {
-    my ($self, $app) = @_;
-
+sub register ($self, $app) {
     my $max = $app->config->{global}{max_rss_limit};
     return unless $max && $max > 0;