fix changelog ref link, add explanation for package version file validation

Author: brainelectronics

.github/workflows/test.yml

@@ -41,6 +41,9 @@ jobs:
         run: |
           yamllint .
       - name: Validate package version file
+        # the package version file has to be always up to date as mip is using
+        # the file directly from the repo. On a PyPi package the version file
+        # is updated and then packed
         run: |
           changelog2version \
             --changelog_file changelog.md \

changelog.md

@@ -130,8 +130,9 @@ r"^\#\# \[\d{1,}[.]\d{1,}[.]\d{1,}\] \- \d{4}\-\d{2}-\d{2}$"
 - [`setup.py`](setup.py) and [`sdist_upip.py`](sdist_upip.py) file
 
 <!-- Links -->
-[Unreleased]: https://github.com/brainelectronics/micropython-package-template/compare/0.8.1...main
+[Unreleased]: https://github.com/brainelectronics/micropython-package-template/compare/0.9.0...main
 
+[0.9.0]: https://github.com/brainelectronics/micropython-package-template/tree/0.9.0
 [0.8.1]: https://github.com/brainelectronics/micropython-package-template/tree/0.8.1
 [0.8.0]: https://github.com/brainelectronics/micropython-package-template/tree/0.8.0
 [0.7.0]: https://github.com/brainelectronics/micropython-package-template/tree/0.7.0