chore: improve pull request template (#7576)

Co-authored-by: Rhys Arkins <rhys@arkins.net>

.github/pull_request_template.md

@@ -1,9 +1,26 @@
-<!-- Before submitting a Pull Request, please ensure you have signed the CLA using this GitHub App: https://cla-assistant.io/renovatebot/renovate -->
+<!-- If this is your first pull request: sign the CLA with this GitHub app: https://cla-assistant.io/renovatebot/renovate -->
+<!-- Make sure the `Allow edits and access to secrets by maintainers` checkbox is checked on this pull request. -->
 
-<!-- When creating this PR on GitHub, please ensure `Allow edits from maintainers.` checkbox is checked -->
+## Changes:
 
-<!-- Please use a conventional commit message (https://www.conventionalcommits.org/en/v1.0.0/) as your PR title -->
+<!-- Describe what this pull request changes. -->
 
-<!-- Ideally include at least one sentence saying what this PR achieves -->
+## Context:
 
-<!-- Finish the PR with `Closes #` and then the issue number if it closes any associated issue -->
+<!-- Describe why you're making these changes if it's not already explained in a corresponding issue. -->
+<!-- If you're closing an existing issue with this pull request, use the keyword Closes #issue_number -->
+
+## Documentation (please check one with an [x])
+
+- [ ] I have updated the documentation, or
+- [ ] No documentation update is required
+
+## How I've tested my work (please tick one)
+
+I have verified these changes via:
+
+- [ ] Code inspection only, or
+- [ ] Newly added unit tests, or
+- [ ] Unit tests + ran on a real repository
+
+<!-- Do you have any suggestions about this PR template? Edit it here: https://github.com/renovatebot/renovate/edit/master/.github/pull_request_template.md -->