feat: add trigger_error E_USER_DEPRECATED

Author: kenjis

system/Filters/Filters.php

@@ -505,6 +505,11 @@ protected function processMethods()
         // @deprecated 4.5.0
         // @TODO remove this in the future.
         elseif (array_key_exists(strtolower($method), $this->config->methods)) {
+            @trigger_error(
+                'Setting lowercase HTTP method key "' . $method . '" is deprecated. Use uppercase HTTP method like "GET".',
+                E_USER_DEPRECATED
+            );
+
             $found  = true;
             $method = strtolower($method);
         }

system/Router/RouteCollection.php

@@ -1012,6 +1012,13 @@ public function match(array $verbs = [], string $from = '', $to = '', ?array $op
         }
 
         foreach ($verbs as $verb) {
+            if ($verb === strtolower($verb)) {
+                @trigger_error(
+                    'Passing lowercase HTTP method "' . $verb . '" is deprecated. Use uppercase HTTP method like "GET".',
+                    E_USER_DEPRECATED
+                );
+            }
+
             /**
              * @TODO We should use correct uppercase verb.
              * @deprecated 4.5.0

system/Test/FeatureTestTrait.php

@@ -51,6 +51,13 @@ protected function withRoutes(?array $routes = null)
             $collection->resetRoutes();
 
             foreach ($routes as $route) {
+                if ($route[0] = strtolower($route[0])) {
+                    @trigger_error(
+                        'Passing lowercase HTTP method "' . $route[0] . '" is deprecated. Use uppercase HTTP method like "GET".',
+                        E_USER_DEPRECATED
+                    );
+                }
+
                 /**
                  * @TODO For backward compatibility. Remove strtolower() in the future.
                  * @deprecated 4.5.0