Update contributing url on PR template

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,13 +1,14 @@
 <!-- Thank you for taking the time to work on a Pull Request for this project! -->
 <!-- To ensure your PR is dealt with swiftly please check the following: -->
-- [ ] My submission is formatted according to the guidelines in the [contributing guide](/CONTRIBUTING.md)
-- [ ] My addition is ordered alphabetically
-- [ ] My submission has a useful description
-- [ ] The description does not have more than 100 characters
-- [ ] The description does not end with punctuation
-- [ ] Each table column is padded with one space on either side
-- [ ] I have searched the repository for any relevant issues or pull requests
-- [ ] Any category I am creating has the minimum requirement of 3 items
-- [ ] All changes have been [squashed][squash-link] into a single commit
 
-[squash-link]: <https://github.com/todotxt/todo.txt-android/wiki/Squash-All-Commits-Related-to-a-Single-Issue-into-a-Single-Commit>
+-   [ ] My submission is formatted according to the guidelines in the [contributing guide](https://github.com/public-apis-dev/public-apis/blob/main/CONTRIBUTING.md)
+-   [ ] My addition is ordered alphabetically
+-   [ ] My submission has a useful description
+-   [ ] The description does not have more than 100 characters
+-   [ ] The description does not end with punctuation
+-   [ ] Each table column is padded with one space on either side
+-   [ ] I have searched the repository for any relevant issues or pull requests
+-   [ ] Any category I am creating has the minimum requirement of 3 items
+-   [ ] All changes have been [squashed][squash-link] into a single commit
+
+[squash-link]: https://github.com/todotxt/todo.txt-android/wiki/Squash-All-Commits-Related-to-a-Single-Issue-into-a-Single-Commit