Add issue template and other fixes

Author: mosuem

.github/ISSUE_TEMPLATE/stack_trace.md

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

pkgs/stack_trace/pubspec.yaml

@@ -1,7 +1,7 @@
 name: stack_trace
 version: 1.12.0
 description: A package for manipulating stack traces and printing them readably.
-repository: https://github.com/dart-lang/stack_trace
+repository: https://github.com/dart-lang/tools/tree/main/pkgs/stack_trace
 
 environment:
   sdk: ^3.4.0