docs: add pull request template

Mirror the Ionic Framework PR template so contributors get a consistent
structure: issue reference, current/new behavior, a breaking-change
checkbox with migration guidance, and an other-information section. The
breaking-change note points at this repo's BREAKING.md and the
Conventional Commits footer format used by the publish pipeline.

Author: gnbm

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,34 @@
+Issue number: resolves #
+
+---------
+
+<!-- Please do not submit updates to dependencies unless it fixes an issue. -->
+
+<!-- Please try to limit your pull request to one type (bugfix, feature, etc). Submit multiple pull requests if needed. -->
+
+## What is the current behavior?
+<!-- Please describe the current behavior that you are modifying. -->
+
+## What is the new behavior?
+<!-- Please describe the behavior or changes that are being added by this PR. -->
+
+-
+-
+-
+
+## Does this introduce a breaking change?
+
+- [ ] Yes
+- [ ] No
+
+<!--
+  If this introduces a breaking change:
+  1. Describe the impact and migration path for existing applications below.
+  2. Update the BREAKING.md file with the breaking change.
+  3. Add "BREAKING CHANGE: [...]" to the commit description when merging. See https://www.conventionalcommits.org/ for more information.
+-->
+
+
+## Other information
+
+<!-- Any other information that is important to this PR such as screenshots of how the change behaves before and after. -->