meta: add pull request template (#898)

Co-authored-by: Lorenzo Cian <[email protected]>

Author: dingsdax

.github/pull_request_template.md

@@ -0,0 +1,14 @@
+### Description
+<!-- What changed and why? -->
+
+#### Issues
+<!--
+* resolves: #1234
+* resolves: LIN-1234
+-->
+
+#### Reminders
+- Add GH Issue ID _&_ Linear ID (if applicable)
+- Add an entry to CHANGELOG.md, following the format of existing entries
+- The PR title should use [Conventional Commits](https://develop.sentry.dev/engineering-practices/commit-messages/#type) style (`feat:`, `fix:`, `ref:`, `meta:`, etc.)
+- Useful links for external contributors: [Sentry SDK development docs](https://develop.sentry.dev/sdk/), [Discord community](https://discord.gg/sentry)