Edit pull request template (#22)

**User-Facing Changes**
There is no user-facing changes

**Description**

Adding a checklist to remind the developer about the checks that we
agreed to perform before merging a PR.

.github/pull_request_template.md

@@ -7,3 +7,10 @@
 <!-- link relevant GitHub issues -->
 <!-- add `docs` label if this PR requires documentation updates -->
 <!-- add relevant metric tracking for experimental / new features -->
+
+**Checklist**
+
+- [ ] The web version was tested and it is running ok
+- [ ] The desktop version was tested and it is running ok
+- [ ] I've updated/created the storybook file(s)
+- [ ] The release version was updated on package.json files