build(config): prepare ReVoltVPN 3.3.5 release

Bump the app version and document the 3.3.5 changes while preserving the published 3.3.4 release history.

pubspec.yaml

@@ -15,7 +15,7 @@ publish_to: "none" # Remove this line if you wish to publish to pub.dev
 # In iOS, build-name is used as CFBundleShortVersionString while build-number used as CFBundleVersion.
 # Read more about iOS versioning at
 # https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
-version: 3.3.4+30
+version: 3.3.5+31
 
 environment:
   sdk: ">=3.0.0 <4.0.0"