Add PR template (#416)

* Add PR template

* Remove line about not using fixes

* Add notes about CLA and release notes

.github/pull_request_template.md

@@ -0,0 +1,31 @@
+<!--  Thanks for sending a pull request!  Here are some tips for you:
+
+1. Ensure that your code follows our code conventions: https://github.com/gojek/feast/blob/master/docs/contributing.md#code-conventions
+2. Run unit tests and ensure that they are passing: https://github.com/gojek/feast/blob/master/docs/contributing.md#running-unit-tests
+3. If your change introduces any API changes, make sure to update the integration tests scripts here: https://github.com/gojek/feast/tree/master/tests/e2e
+4. Make sure documentation is updated for your PR!
+5. Make sure you have signed the CLA https://cla.developers.google.com/clas
+
+-->
+
+**What this PR does / why we need it**:
+
+**Which issue(s) this PR fixes**:
+<!--
+*Automatically closes linked issue when PR is merged.
+Usage: `Fixes #<issue number>`, or `Fixes (paste link of issue)`.
+-->
+Fixes #
+
+**Does this PR introduce a user-facing change?**:
+<!--
+If no, just write "NONE" in the release-note block below.
+If yes, a release note is required:
+Enter your extended release note in the block below. If the PR requires additional action from users switching to the new release, include the string "action required".
+
+For more information about release notes, see kubernetes' guide here:
+http://git.k8s.io/community/contributors/guide/release-notes.md
+-->
+```release-note
+
+```