chore: add PR template (#545)

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,16 @@
+# Description
+
+Please include a summary of the change and which issue is fixed. Please also include relevant motivation and context.
+
+Fixes # (issue)
+
+# How Has This Been Tested?
+
+Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration.
+
+# Checklist:
+
+- [ ] My changes follow the guidelines in [CONTRIBUTING.md](https://github.com/dfinity/agent-js/blob/main/CONTRIBUTING.md).
+- [ ] The title of this PR complies with [Conventional Commits](https://www.conventionalcommits.org/en/v1.0.0/).
+- [ ] I have edited the CHANGELOG accordingly.
+- [ ] I have made corresponding changes to the documentation.