Update pull request template (#10142)

* Update pull request template

* Changes as requested

* Link to https://developers.mattermost.com/contribute/server/developer-workflow/#running-only-specific-server-unit-tests

* Move PR and issue template to .github

* Update per feedback

See https://community.mattermost.com/core/pl/1ikmqhzw1ffsfepzyb4575bkih

* Changes as requested

* Remove checklist

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,20 @@
+<!-- Thank you for contributing a pull request! Here are a few tips to help you:
+
+1. If this is your first contribution, make sure you've read the Contribution Checklist https://developers.mattermost.com/contribute/getting-started/contribution-checklist/
+2. Read our blog post about "Submitting Great PRs" https://developers.mattermost.com/blog/2019-01-24-submitting-great-prs
+3. Take a look at other repository specific documentation at https://developers.mattermost.com/contribute
+-->
+
+#### Summary
+<!--
+A description of what this pull request does.
+-->
+
+#### Ticket Link
+<!--
+If this pull request addresses a Help Wanted ticket, please link the relevant GitHub issue, e.g.
+
+  Fixes https://github.com/mattermost/mattermost-server/issues/XXXXX
+
+Otherwise, link the JIRA ticket.
+-->

PULL_REQUEST_TEMPLATE.md

@@ -1,19 +0,0 @@
-Please make sure you've read the [pull request](http://docs.mattermost.com/developer/contribution-guide.html#preparing-a-pull-request) section of our [code contribution guidelines](http://docs.mattermost.com/developer/contribution-guide.html).
-
-When filling in a section please remove the help text and the above text.
-
-#### Summary
-[A brief description of what this pull request does.]
-
-#### Ticket Link
-[Please link the GitHub issue or Jira ticket this PR addresses.]
-
-#### Checklist
-[Place an '[x]' (no spaces) in all applicable fields. Please remove unrelated fields.]
-- [ ] Added or updated unit tests (required for all new features)
-- [ ] Added API documentation (required for all new APIs)
-- [ ] All new/modified APIs include changes to the drivers
-- [ ] Has enterprise changes (please link)
-- [ ] Has UI changes
-- [ ] Includes text changes and localization file ([.../i18n/en.json](https://github.com/mattermost/mattermost-server/blob/master/i18n/en.json)) updates
-- [ ] Touches critical sections of the codebase (auth, upgrade, etc.)