Add draft pull request template

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,35 @@
+**Important:** External contributors must comply with the template, otherwise PRs may be closed without further notice.
+
+
+## Description
+
+<!-- Explain your changes -->
+
+
+## Checklist
+
+<!--
+- Choose the section(s) relevant to your PR, read its questions carefully and answer truthfully. (Never mind inapplicable sections - e.g. if the PR doesn't change setup code, you needn't handle the setup section.)
+- Place an `x` in the `[ ]` for "yes", leave it empty for "no". If a question is not applicable, remove the `[ ]`.
+- Use the Preview tab to confirm the PR will render correctly.
+-->
+
+
+### Setup
+
+- [ ] This PR changes setup code (`setupsrc/`, `setup.py`).
+- [ ] If acting on behalf of a downstream use case, I have assessed that it cannot reasonably be solved by existing means, or the change forms a significant improvement over possible alternatives.
+- [ ] I believe the change is maintainable and does not cause unreasonable complexity or code pollution.
+- [ ] I believe the targeted use case is supported by pypdfium2-team. *Note that this project tends to be unwilling to support esoteric or artificially restricted setup envs.*
+
+
+### Helpers
+
+- [ ] This PR changes helpers code.
+- [ ] The change comes with sufficient test cases to confirm correct functionality.
+- [ ] Any new test files are under a suitable license and have been registered in `reuse/dep5`.
+
+
+### Other
+
+- [ ] This PR changes other things, namely: ... <!-- briefly specify what was changed -->

.reuse/dep5

@@ -14,10 +14,10 @@ Source: https://github.com/pypdfium2-team/pypdfium2
 # License: ...
 
 Files:
-    RELEASE.md
     req/*.txt
     autorelease/record.json
     autorelease/config.json
+    .github/PULL_REQUEST_TEMPLATE.md
     tests/expectations/*
     tests/resources/render.pdf
     tests/resources/multipage.pdf