Add optional template changelog to root changelog

Author: sverhoeven

CHANGELOG.md

@@ -13,6 +13,7 @@
 
 ### Changed
 
+* CHANGELOG.md is now optional ([#462](https://github.com/NLeSC/python-template/issues/462))
 * Moved to src/ based layout for generated packages
 * Moved from setup.cfg/.py to pyproject.toml [#351](https://github.com/NLeSC/python-template/issues/351)
 * Moved from prospector to ruff [#336](https://github.com/NLeSC/python-template/issues/336)