Refactor changelog-related files (#265)

* Refactor changelog-related files

* Fix heading level in changelog

* docs: add changelog to index

* docs: move changelog (delete original)

---------

Co-authored-by: Yanks Yoon <[email protected]>
Co-authored-by: Yanks Yoon <[email protected]>

Author: yhaliaw

.github/pull_request_template.md

@@ -28,5 +28,6 @@ Applicable spec: <link>
 - [ ] The documentation for charmhub is updated.
 - [ ] The changelog `docs/changelog.md` is updated.
 - [ ] The PR is tagged with appropriate label (`urgent`, `trivial`, `complex`)
+- [ ] The docs/changelog.md is updated with user-relevant changes in the format of [keep a changelog v1.1.0](https://keepachangelog.com/en/1.1.0/)
 
 <!-- Explanation for any unchecked items above -->

docs/changelog.md

@@ -1,5 +1,11 @@
 # Changelog
 
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
+
+Each revision is versioned by the date of the revision.
+
 ### 20250-03-11
 
 - docs: fix charm architecture diagram (separate charm containers boundary)

docs/index.md

@@ -55,3 +55,4 @@ Thinking about using the WordPress Operator for your next project? [Get in touch
   1. [Themes](reference/themes.md)
 1. [Explanation](explanation)
   1. [Charm architecture](explanation/charm-architecture.md)
+1. [Changelog](changelog.md)