Update extract_release_notes_for_version_action details

While testing Automattic/pocket-casts-ios#149, I
noticed the `details` for this action were incorrect.

Author: mokagio

lib/fastlane/plugin/wpmreleasetoolkit/actions/common/extract_release_notes_for_version_action.rb

@@ -58,7 +58,7 @@ def self.return_value
 
       def self.details
         # Optional:
-        'Creates a release and uploads the provided assets'
+        'Given a file containing release notes and a version, extracts the notes for that version into a dedicated file.'
       end
 
       def self.available_options