Add nullable value to getApplication method

Author: Pavlusha311245

src/Config.php

@@ -153,11 +153,11 @@ public function getApplications(): array
      * Get application from config by name
      *
      * @param $applicationName
-     * @return mixed
+     * @return ApplicationAbstract|null
      */
-    public function getApplication($applicationName): ApplicationAbstract
+    public function getApplication($applicationName): ?ApplicationAbstract
     {
-        return $this->_applications[$applicationName];
+        return $this->_applications[$applicationName] ?? null;
     }
 
     /**

src/Interfaces/ConfigInterface.php

@@ -59,9 +59,9 @@ public function getApplications(): array;
 
     /**
      * @param $applicationName
-     * @return ApplicationAbstract
+     * @return ApplicationAbstract|null
      */
-    public function getApplication($applicationName): ApplicationAbstract;
+    public function getApplication($applicationName): ?ApplicationAbstract;
 
     /**
      * @param ApplicationAbstract $application