Add issue template

Author: adamwathan

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,11 @@
+<!--
+
+👋 Hey, thanks for taking an interest in Tailwind!
+
+Please only open an issue here if you have a bug to report or a feature proposal you'd like to discuss.
+
+If you need help, have questions about best practices, or want to start a discussion about anything else related to Tailwind, open an issue on the `tailwindcss/discuss` repo instead:
+
+https://github.com/tailwindcss/discuss/issues
+
+-->