add issue template

Author: helfer

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,25 @@
+<!--
+  Thanks for filing an issue on Apollo Client!
+
+  Please look at the following checklist to ensure that your issue is actionable.
+-->
+
+**Intended outcome:**
+
+
+**Actual outcome:**
+
+
+**How to reproduce the issue:**
+
+
+<!-- 
+**Intended outcome:**
+What you were trying to accomplish when the bug occurred, and as much code as possible related to the source of the problem.
+
+**Actual outcome:**
+A description of what actually happened, including a screenshot or copy-paste of any related error messages, logs, or other output that might be related. Places to look for information include your browser console, server console, and network logs. Please avoid non-specific phrases like “didn’t work” or “broke”.
+
+**How to reproduce the issue:**
+Instructions for how the issue can be reproduced by a maintainer or contributor. Be as specific as possible, and only mention what is necessary to reproduce the bug. If possible, try to isolate the exact circumstances in which the bug occurs and avoid speculation over what the cause might be.
+-->