refactor(core): call invokable classes with invoke (#799)

Author: innocenzi

src/Tempest/Core/src/Kernel.php

@@ -118,21 +118,21 @@ public function registerShutdownFunction(): self
 
     public function loadDiscoveryLocations(): self
     {
-        ($this->container->get(LoadDiscoveryLocations::class))();
+        $this->container->invoke(LoadDiscoveryLocations::class);
 
         return $this;
     }
 
     public function loadDiscovery(): self
     {
-        ($this->container->get(LoadDiscoveryClasses::class))();
+        $this->container->invoke(LoadDiscoveryClasses::class);
 
         return $this;
     }
 
     public function loadConfig(): self
     {
-        $this->container->get(LoadConfig::class)();
+        $this->container->invoke(LoadConfig::class);
 
         return $this;
     }
@@ -160,7 +160,7 @@ public function registerErrorHandler(): self
 
     public function finishDeferredTasks(): self
     {
-        ($this->container->get(FinishDeferredTasks::class))();
+        $this->container->invoke(FinishDeferredTasks::class);
 
         return $this;
     }