Update android-app.md
Adding a link to Bazel's open feature requests and issues page (per conversation with Joe).
Closes
@@ -396,6 +396,7 @@ installing it.
For more details, see these pages:
+* Open issues on [GitHub](https://github.com/bazelbuild/bazel/issues)
* More information on [mobile-install](../mobile-install.md)
* Integrate external dependencies like AppCompat, Guava and JUnit from Maven
repositories using [rules_jvm_external](https://github.com/bazelbuild/rules_jvm_external)
