Server error (#182)

* inherit error

* update changelog

Author: KazuCocoa

CHANGELOG.md

@@ -6,6 +6,7 @@ Read `release_notes.md` for commit level details.
 ### Enhancements
 
 ### Bug fixes
+- Inherit CoreError for ServerError in order to handle it as an exception
 
 ### Deprecations
 

lib/appium_lib_core/common/error.rb

@@ -14,7 +14,7 @@ class NoSuchElementError < CoreError; end
       class UnsupportedOperationError < CoreError; end
 
       # Server side error
-      class ServerError; end
+      class ServerError < CoreError; end
     end
   end
 end