Simplify PR template

Signed-off-by: Yuki Kishimoto <yukikishimoto@protonmail.com>

.github/pull_request_template.md

@@ -1,5 +1,3 @@
-<!-- You can erase any parts of this template not applicable to your Pull Request. -->
-
 ### Description
 
 <!-- Describe the purpose of this PR, what's being adding and/or fixed -->
@@ -9,24 +7,8 @@
 <!-- In this section you can include notes directed to the reviewers, like explaining why some parts
 of the PR were done in a specific way -->
 
-### Changelog notice
-
-<!-- Add the changelog -->
-
-### Checklists
-
-#### All Submissions:
+### Checklist
 
 * [ ] I followed the [contribution guidelines](https://github.com/rust-nostr/nostr/blob/master/CONTRIBUTING.md)
 * [ ] I ran `just precommit` or `just check` before committing
-
-#### New Features:
-
-* [ ] I've added tests for the new feature
-* [ ] I've added docs for the new feature
-
-#### Bugfixes:
-
-* [ ] This pull request breaks the existing API
-* [ ] I've added tests to reproduce the issue which are now passing
-* [ ] I'm linking the issue being fixed by this PR
+* [ ] I updated the [CHANGELOG](https://github.com/rust-nostr/nostr/blob/master/CHANGELOG.md) (if applicable)