Update PR template

Author: znichollscr

.github/pull_request_template.md

@@ -4,5 +4,8 @@
 
 Please confirm that this pull request has done the following:
 
+- [ ] Data released on ESGF
+- [ ] ESGF update pulled in here
 - [ ] Documentation added (where applicable)
 - [ ] Changelog item added to `changelog/`
+- [ ] Did a new release after merging