Adds a PR template

**What kind of PR is this?**
<!--
For example:
- Bug fix
- Enhancement
- Feature
-->

Documentation / GitHub

**What does does this PR do / why we need it**:

This adds a PR template whenver someone opens a new PR.

**Which issue(s) this PR fixes**:

N/A

**How to test changes / Special notes to the reviewer**:

N/A

<!---
Example:
```sh
helm install
your steps here
```
-->

Signed-off-by: Charlie Drage <charlie@charliedrage.com>

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,25 @@
+<!--  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 kind of PR is this?**
+<!--
+For example:
+- Bug fix
+- Enhancement
+- Feature
+-->
+
+**What does does this PR do / why we need it**:
+
+**Which issue(s) this PR fixes**:
+
+Fixes #?
+
+**How to test changes / Special notes to the reviewer**:
+
+<!---
+Example:
+```sh
+helm install
+```