Adding PR template from dev-v2 branch

Signed-off-by: Bridget Kromhout <bridget@kromhout.org>

.github/pull_request_template.md

@@ -0,0 +1,12 @@
+<!--  Thanks for sending a pull request!  Here are some tips for you:
+1. Make sure to read the Contributing Guide before submitting your PR: https://github.com/helm/helm/blob/master/CONTRIBUTING.md
+2. If this PR closes another issue, add 'closes #<issue number>' somewhere in the PR summary. GitHub will automatically close that issue when this PR gets merged. Alternatively, adding 'refs #<issue number>' will not close the issue, but help provide the reviewer more context.-->
+
+**What this PR does / why we need it**:
+
+**Special notes for your reviewer**:
+
+**If applicable**:
+- [ ] this PR contains documentation
+- [ ] this PR contains unit tests
+- [ ] this PR has been tested for backwards compatibility