fix: Call to a member function requestIsConditional() on null (dingo#1377)

* fix: Call to a member function requestIsConditional() on null
* fix: delete old version, use new version

Author: jingyu525

src/Routing/Adapter/Lumen.php

@@ -107,6 +107,7 @@ public function dispatch(Request $request, $version)
         $this->removeMiddlewareFromApp();
 
         $routeCollector = $this->mergeOldRoutes($version);
+
         $dispatcher = call_user_func($this->dispatcherResolver, $routeCollector);
 
         $this->app->setDispatcher($dispatcher);

src/Routing/Router.php

@@ -402,6 +402,10 @@ protected function mergeGroup(array $new, array $old)
             $new[$option] = $this->formatArrayBasedOption($option, $new);
         }
 
+        if (isset($new['version'])) {
+            unset($old['version']);
+        }
+
         if (isset($new['domain'])) {
             unset($old['domain']);
         }
@@ -588,7 +592,7 @@ public function gatherRouteMiddlewares($route)
      */
     protected function requestIsConditional()
     {
-        return $this->getCurrentRoute()->requestIsConditional();
+        return ($r = $this->getCurrentRoute()) ? $r->requestIsConditional() : false;
     }
 
     /**