docs: add issue template

Author: marionebl

ISSUE_TEMPLATE.md

@@ -0,0 +1,48 @@
+<!--- Provide a general summary of the issue in the Title above -->
+
+## Expected Behavior
+<!--- If you're describing a bug, tell us what should happen -->
+<!--- If you're suggesting a change/improvement, tell us how it should work -->
+
+## Current Behavior
+<!--- If describing a bug, tell us what happens instead of the expected behavior -->
+<!--- If suggesting a change/improvement, explain the difference from current behavior -->
+
+## Affected packages
+* [ ] cli
+* [ ] core
+* [ ] prompt
+* [ ] config-angular
+
+## Possible Solution
+<!--- Not obligatory, but suggest a fix/reason for the bug, -->
+<!--- or ideas how to implement the addition or change -->
+
+## Steps to Reproduce (for bugs)
+<!--- Provide a link to a live example, or an unambiguous set of steps to -->
+<!--- reproduce this bug. Include code to reproduce, if relevant -->
+1.
+2.
+3.
+4.
+
+<details>
+  <summary>commitlint.config.js</summary>
+  <!-- If you have a `commitlint.config.js` available, please paste it here -->
+  <!-- Otherwise, feel free to delete this <details> block -->
+```js
+```
+</details>
+
+## Context
+<!--- How has this issue affected you? What are you trying to accomplish? -->
+<!--- Providing context helps us come up with a solution that is most useful in the real world -->
+
+## Your Environment
+<!--- Include as many relevant details about the environment you experienced the bug in -->
+
+| Executable | Version |
+| ---: | :--- |
+| `commitlint --version` | VERSION |
+| `git --version`  | VERSION |
+| `node --version` | VERSION |