docs: add changeset to contributing guide

Author: bholmesdev

CONTRIBUTING.md

@@ -78,4 +78,12 @@ You can also run packages _and_ examples simultaneously:
 pnpm dev:all
 ```
 
-However, we've found console logs are harder to read using this approach. Use whichever you prefer!
+However, we've found console logs are harder to read using this approach. Use whichever you prefer!
+
+## Making a Pull Request
+
+When making a pull request, be sure to add a changeset when a package has changed. Non-packages (`examples/*`) do not need changesets.
+
+```bash
+pnpm exec changeset
+```