document that changelog entries don't need refs

Author: mhils

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## Unreleased: pdoc next
 
+<!-- ✨ You do not need to add a pull request reference or an author, this will be added automatically by CI. ✨ -->
+
  - Docstrings can now include local images which will be embedded into the page, e.g. `![image](./image.png)`.
    ([#282](https://github.com/mitmproxy/pdoc/issues/282), @mhils)
  - Fix a bug in parsing Google-style docstrings with extraneous whitespace.