Add issue template and other fixes

Author: mosuem

.github/ISSUE_TEMPLATE/fake_async.md

@@ -0,0 +1,5 @@
+---
+name: "package:fake_async"
+about: "Create a bug or file a feature request against package:fake_async."
+labels: "package:fake_async"
+---

pkgs/fake_async/pubspec.yaml

@@ -3,7 +3,7 @@ version: 1.3.2-wip
 description: >-
   Fake asynchronous events such as timers and microtasks for deterministic
   testing.
-repository: https://github.com/dart-lang/fake_async
+repository: https://github.com/dart-lang/test/tree/main/pkgs/fake_async
 
 environment:
   sdk: ^3.3.0