chore(pubspec)!: 2.3.0

bumps minimum language version to 3.6
since it's required for correct type checks

Author: Zekfad

pubspec.yaml

@@ -1,6 +1,6 @@
 name: fetch_api
 description: JavaScript bindings for Fetch API, flexible HTTP requests, redirects, streaming and more.
-version: 2.2.1
+version: 2.3.0
 homepage: https://github.com/Zekfad/fetch_api
 repository: https://github.com/Zekfad/fetch_api
 issue_tracker: https://github.com/Zekfad/fetch_api/issues
@@ -13,7 +13,7 @@ platforms:
   web:
 
 environment:
-  sdk: '>=3.4.0 <4.0.0'
+  sdk: '>=3.6.0 <4.0.0'
 
 dependencies:
   # no upper bound, because we use only Types