Update issue templates (#794)

Author: brianquinlan

.github/ISSUE_TEMPLATE/package-cronet_http---i-d-like-a-new-feature.md

@@ -0,0 +1,11 @@
+---
+name: package:cronet_http - I'd like a new feature
+about: You are using package:cronet_http and would like a new feature to make it easier
+  to make http requests.
+title: ''
+labels: package:cronet_http, type-enhancement
+assignees: brianquinlan
+
+---
+
+

.github/ISSUE_TEMPLATE/package-cronet_http---i-found-a-bug.md

@@ -0,0 +1,10 @@
+---
+name: package:cronet_http - I found a bug
+about: You found that something which is expected to work, doesn't.
+title: ''
+labels: package:cronet_http, type-bug
+assignees: brianquinlan
+
+---
+
+

.github/ISSUE_TEMPLATE/package-cupertino_http---i-d-like-a-new-feature.md

@@ -0,0 +1,11 @@
+---
+name: package:cupertino_http - I'd like a new feature
+about: You are using package:cupertino_http and would like a new feature to make it
+  easier to make http requests.
+title: ''
+labels: package:cupertino_http, type-enhancement
+assignees: brianquinlan
+
+---
+
+

.github/ISSUE_TEMPLATE/package-cupertino_http---i-found-a-bug.md

@@ -0,0 +1,10 @@
+---
+name: package:cupertino_http - I found a bug
+about: You found that something which is expected to work, doesn't.
+title: ''
+labels: package:cupertino_http, type-bug
+assignees: brianquinlan
+
+---
+
+

.github/ISSUE_TEMPLATE/package-http---failing-connection.md

@@ -0,0 +1,37 @@
+---
+name: package:http - Failing Connection
+about: You are attempting to make a GET or POST and getting an unexpected   exception
+  or status code.
+title: ''
+labels: package:http, type-bug
+assignees: ''
+
+---
+
+**********************************************************
+**This is not the repository you want to file issues in!**
+**********************************************************
+
+Note that a failing HTTP connection is almost certainly not caused by a bug in
+package:http.
+
+This package is a wrapper around the HttpClient from dart:io and HttpRequest
+from dart:html. Before filing a bug here verify that the issue is not surfaced
+when using those interfaces directly.
+
+https://api.dart.dev/stable/dart-io/HttpClient-class.html
+https://api.dart.dev/stable/dart-html/HttpRequest-class.html
+
+# Common problems:
+
+- A security policy prevents the connection.
+- Running in an emulator that does not have outside internet access.
+- Using Android and not requesting internet access in the manifest.
+  https://github.com/flutter/flutter/issues/29688
+
+None of these problems are influenced by the code in this repo.
+
+# Diagnosing:
+
+- Attempt the request outside of Dart, for instance in a browser or with `curl`.
+- Attempt the request with the dart:io or dart:html equivalent code paths.

.github/ISSUE_TEMPLATE/package-http---i-d-like-a-new-feature.md

@@ -0,0 +1,11 @@
+---
+name: package:http - I'd like a new feature
+about: You are using package:http and would like a new feature to make it  easier
+  to make http requests.
+title: ''
+labels: package:http, type-enhancement
+assignees: ''
+
+---
+
+

.github/ISSUE_TEMPLATE/package-http---i-found-a-bug.md

@@ -0,0 +1,15 @@
+---
+name: package:http - I found a bug
+about: You found that something which is expected to work, doesn't. The same   capability
+  works when using `dart:io` or `dart:html` directly.
+title: ''
+labels: package:http, type-bug
+assignees: ''
+
+---
+
+Please describe the bug and how to reproduce it.
+
+Note that if the bug can also be reproduced when going through the interfaces provided by `dart:html` or `dart:io` directly the bug should be filed against the Dart SDK: https://github.com/dart-lang/sdk/issues
+
+A failure to make an http request is more often a problem with the environment than with the client.