chore: add pull request template (#3294)

Signed-off-by: Will Murphy <willmurphyscode@users.noreply.github.com>

.github/pull_request_template.md

@@ -0,0 +1,25 @@
+# Description
+
+Please include a summary of the changes along with any relevant motivation and context,
+or link to an issue where this is explained.
+
+<!-- If this completes an issue, please include: -->
+
+- Fixes #
+
+## Type of change
+
+<!-- Delete any that are not relevant -->
+
+- [ ] Bug fix (non-breaking change which fixes an issue)
+- [ ] New feature (non-breaking change which adds functionality)
+- [ ] Breaking change (please discuss with the team first; Syft is 1.0 software and we won't accept breaking changes without going to 2.0)
+- [ ] Documentation (updates the documentation)
+- [ ] Chore (improve the developer experience, fix a test flake, etc, without changing the visible behavior of Syft)
+- [ ] Performance (make Syft run faster or use less memory, without changing visible behavior much)
+
+# Checklist:
+
+- [ ] I have added unit tests that cover changed behavior
+- [ ] I have tested my code in common scenarios and confirmed there are no regressions
+- [ ] I have added comments to my code, particularly in hard-to-understand sections