Update gh pull request template

Perhaps exposing some our critical pull requests requirements in a checklist might help users.  As of now, we do this as a "soft open".

Co-authored-by: Jan Rodák <hony.com@seznam.cz>
Co-authored-by: Ashley Cui <ashleycui16@gmail.com>
Signed-off-by: Brent Baude <bbaude@redhat.com>

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,23 +1,30 @@
 <!--
 Thanks for sending a pull request!
 
-Please make sure you've read our contributing guidelines and how to submit a pull request (https://github.com/containers/podman/blob/main/CONTRIBUTING.md#submitting-pull-requests).
+For more detailed information, please review our contributing guidelines:
-
+https://github.com/containers/podman/blob/main/CONTRIBUTING.md#submitting-pull-requests
-Finally, be sure to sign commits with your real name. Since by opening
-a PR you already have commits, you can add signatures if needed with
-something like `git commit -s --amend`.
 -->
 
+#### Checklist
+
+Ensure you have completed the following checklist for your pull request to be reviewed:
+<!-- Use [x] to mark as done, or click the checkbox after opening PR -->
+
+- [ ] Certify you wrote the patch or otherwise have the right to pass it on as an open-source patch by signing all
+commits. (`git commit -s`). (If needed, use `git commit -s --amend`).  The author email must match
+the sign-off email address. See [CONTRIBUTING.md](https://github.com/containers/podman/blob/main/CONTRIBUTING.md#sign-your-prs)
+for more information.
+- [ ] Referenced issues using `Fixes: #00000` in commit message (if applicable)
+- [ ] [Tests](https://github.com/containers/podman/tree/main/test#readme) have been added/updated (or no tests are needed)
+- [ ] [Documentation](https://github.com/containers/podman/blob/main/docs/README.md) has been updated (or no documentation changes are needed)
+- [ ] All commits pass `make validatepr` (format/lint checks)
+- [ ] [Release note](https://github.com/kubernetes/community/blob/master/contributors/guide/release-notes.md) entered in the section below (or `None` if no user-facing changes)
+
 #### Does this PR introduce a user-facing change?
 
 <!--
-If no, just write `None` in the release-note block below. If yes, a release note
+Write `None` if there are no user-facing changes, otherwise enter your release note below.
-is required: Enter your extended release note in the block below. If the PR
+Include "action required" if users need to take action when upgrading.
-requires additional action from users switching to the new release, include the
-string "action required".
-
-For more information on release notes, please follow the Kubernetes model:
-https://git.k8s.io/community/contributors/guide/release-notes.md
 -->
 
 ```release-note