Add issue and PR templates (#353)

Fixes #352

Co-authored-by: Sindre Sorhus <sindresorhus@gmail.com>

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,32 @@
+---
+name: Bug report
+about: Create a report to help us improve np
+---
+
+<!--- Provide a short summary of the issue in the title above -->
+
+## Description
+
+<!-- Write a clear and concise description of what the issue is -->
+
+## Steps to reproduce
+
+<!--- Let us how how we can reproduce the issue on our end -->
+
+1.
+2.
+3.
+
+## Expected behavior
+
+<!--- Tell us what you expected to happen -->
+
+## Environment
+
+<!-- Mention which versions of np, Node.js, npm and Git you're using, as well as your OS and version -->
+
+np - x.x.x
+Node.js - x.x.x
+npm - x.x.x
+Git - x.x.x
+OS - XXX x.x.x

.github/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,22 @@
+---
+name: Feature request
+about: Suggest an idea
+---
+
+<!--- Provide a short summary of the request in the title above -->
+
+## Description
+
+<!-- Write a clear and concise description of the feature -->
+
+**Is the feature request related to a problem?**
+
+<!-- Describe what the problem is (e.g. I'm always frustrated when […]) -->
+
+## Possible solution
+
+<!-- If possible, let us know how you think the feature should be implemented -->
+
+## Alternatives 
+
+<!-- Include any alternative solutions and features you've considered -->

.github/pull_request_template.md

@@ -0,0 +1,9 @@
+<!--
+
+Thanks for submitting a pull request 🙌
+
+**Note:** Please don't create a pull request which has significant changes (i.e. adds new functionality or modifies existing one in a non-trivial way) without creating an issue first.
+
+Try to limit the scope of your pull request and provide a general description of the changes. If this fixes an open issue, link to it in the following way: `Fixes #321`. New features and bug fixes should come with tests.
+
+-->