Create pull_request_template.md (#2812)

* Create pull_request_template.md

* Update pull_request_template.md

Author: HarHarLinks

.github/pull_request_template.md

@@ -0,0 +1,27 @@
+<!-- Thank you for creating a Pull Request to the matrix.org website!
+     Please read our documentation for contributors to make the review process a smooth as possible:
+     - https://github.com/matrix-org/matrix.org/blob/main/README.md
+     - https://github.com/matrix-org/matrix.org/blob/main/CONTRIBUTING.md
+     - https://github.com/matrix-org/matrix.org/blob/main/CONTENT.md
+
+     You can use the CI build or a local environment to check your changes are working as expected.
+     
+     If you have questions at any time, please contact the Website Working Group at
+     https://matrix.to/#/#matrix.org-website:matrix.org -->
+
+<!-- Please describe what you added, and add a screenshot or video if possible.
+     That makes it easier to understand the change. -->
+
+**:heavy_check_mark: Checklist**
+
+- Check for common mistakes:
+  - [ ] Wrap plain URLs in `<>` to linkify them ([learn more](https://github.com/matrix-org/matrix.org/blob/main/CONTENT.md#publishing-to-the-blog)).
+  - [ ] Use the right level of headings: The page title will use a level 1 headings, so your headings should use level 2 and below.
+  - [ ] Use internal links: when linking to another page on <https://matrix.org>, use absolute `[label](/target)` or relative `[label](subpage)` links.
+- For blog posts:
+  - [ ] Verify the date and post ordering on the `/blog` page, especially for multiple posts on the same day. Prefer UTC format, e.g. `2025-12-01T14:00:00Z` for Dec 1st, 2025, 2pm UTC.
+  - [ ] Set the correct author and category. Browse existing ones at <https://matrix.org/author/> and <https://matrix.org/category/> to match them.
+- [ ] Let us know if you are contributing in a specific role, such as on behalf of an organisation or team, [for example](https://github.com/matrix-org/matrix.org/pull/2788).
+- [ ] Let us know if your PR is time-sensitive in any way.
+- [ ] Mention any issues related to the PR. Use [GitHub keywords](https://docs.github.com/en/issues/tracking-your-work-with-issues/using-issues/linking-a-pull-request-to-an-issue#linking-a-pull-request-to-an-issue-using-a-keyword) as appropriate.
+- [ ] Your individual commits or pull request is [signed off](https://github.com/matrix-org/matrix.org/blob/main/CONTRIBUTING.md).