Add README file changes checkmark

.github/PULL_REQUEST_TEMPLATE.md

@@ -4,6 +4,7 @@ To ensure your PR is dealt with swiftly please check the following:
 
 - [ ] Your submissions are formatted according to the guidelines in the [contributing guide](CONTRIBUTING.md).
 
+- [ ] Your changes are made in the [README](../README.md) file, not the auto-generated JSON. 
 - [ ] Your additions are ordered alphabetically.
 - [ ] Each table column should be padded with one space on either side.
 - [ ] You have searched the repository for any relevant issues or PRs.