add PR template

Author: roycaihw

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,72 @@
+<!--  Thanks for sending a pull request!  Here are some tips for you:
+
+1. If this is your first time, please read our contributor guidelines: https://git.k8s.io/community/contributors/guide/first-contribution.md#your-first-contribution and developer guide https://git.k8s.io/community/contributors/devel/development.md#development-guide
+2. Please label this pull request according to what type of issue you are addressing, especially if this is a release targeted pull request. For reference on required PR/issue labels, read here:
+https://git.k8s.io/community/contributors/devel/sig-release/release.md#issuepr-kind-label
+3. Ensure you have added or ran the appropriate tests for your PR: https://git.k8s.io/community/contributors/devel/sig-testing/testing.md
+4. If you want *faster* PR reviews, read how: https://git.k8s.io/community/contributors/guide/pull-requests.md#best-practices-for-faster-reviews
+5. If the PR is unfinished, see how to mark it: https://git.k8s.io/community/contributors/guide/pull-requests.md#marking-unfinished-pull-requests
+-->
+
+#### What type of PR is this?
+
+<!--
+Add one of the following kinds:
+/kind bug
+/kind cleanup
+/kind documentation
+/kind feature
+/kind design
+
+Optionally add one or more of the following kinds if applicable:
+/kind api-change
+/kind deprecation
+/kind failing-test
+/kind flake
+/kind regression
+-->
+
+#### 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)`.
+_If PR is about `failing-tests or flakes`, please post the related issues/tests in a comment and do not use `Fixes`_*
+-->
+Fixes #
+
+#### Special notes for your reviewer:
+
+#### 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 on release notes see: https://git.k8s.io/community/contributors/guide/release-notes.md
+-->
+```release-note
+
+```
+
+#### Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:
+
+<!--
+This section can be blank if this pull request does not require a release note.
+
+When adding links which point to resources within git repositories, like
+KEPs or supporting documentation, please reference a specific commit and avoid
+linking directly to the master branch. This ensures that links reference a
+specific point in time, rather than a document that may change over time.
+
+See here for guidance on getting permanent links to files: https://help.github.com/en/articles/getting-permanent-links-to-files
+
+Please use the following format for linking documentation:
+- [KEP]: <link>
+- [Usage]: <link>
+- [Other doc]: <link>
+-->
+```docs
+
+```