Add Github Pull Request Template

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,17 @@
+# Description
+
+<!-- Add your description here, if this PR fixes a particular issue please provide a
+[link](https://docs.github.com/en/issues/tracking-your-work-with-issues/linking-a-pull-request-to-an-issue#linking-a-pull-request-to-an-issue-using-a-keyword=)
+to the issue. -->
+
+# Checklist
+
+- [ ] Commit sequence broadly makes sense and commits have useful messages
+- [ ] New tests are added if needed and existing tests are updated
+- [ ] All visible changes are prepended to the latest section of a `CHANGELOG.md` for the affected packages.
+      **_New section is never added with the code changes._** (See [RELEASING.md](https://github.com/intersectmbo/cardano-base/blob/master/RELEASING.md#changelogmd))
+- [ ] When applicable, versions are updated in `.cabal` and `CHANGELOG.md` files according to the
+      [versioning process](https://github.com/intersectmbo/cardano-base/blob/master/RELEASING.md#versioning-process).
+- [ ] The version bounds in `.cabal` files for all affected packages are updated.
+      **_If you change the bounds in a cabal file, that package itself must have a version increase._** (See [RELEASING.md](https://github.com/intersectmbo/cardano-base/blob/master/RELEASING.md#versioning-process))
+- [ ] Self-reviewed the diff