chore(.github): add ISSUE_TEMPLATE

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,39 @@
+Briefly describe the issue you are experiencing (or the feature you want to see
+added to the plugin). Tell us what you were trying to do and what happened
+instead. Remember, this is _not_ a place to ask questions. For that, go to
+http://gitter.im/postcss/postcss
+
+### `Details`
+---
+
+Describe in more detail the problem you have been experiencing, if necessary.
+
+### `Error (Logs|Stacks)`
+---
+
+Create a [gist](https://gist.github.com) which is a paste of your **full**
+logs, and link them here.
+
+Do **not** paste your full logs here (or at least hide them by using a `<details></details>` block), as it will make this issue long and hard
+to read! If you are reporting a bug, **always** include logs!
+
+### `Reproduction [Code]`
+---
+
+Please remember that, with sample code; it's easier to reproduce bug and much
+faster to fix it.
+
+Please refer to a simple code example.
+
+```bash
+$ git clone https://github.com/<user>/<sample>
+```
+
+### `Environment`
+---
+
+Please provide information about your environment.
+
+|OS|node|npm|PostCSS|
+|:-:|:--:|:-:|:------:|
+|[name][version]|[version]|[version]|[version]|