chore: fix files to commit on tag

Makefile

@@ -33,7 +33,7 @@ changelog:
 	@echo -e "  When everything is good, finish the release with 'make tag'."
 
 tag: env
-	git add CHANGELOG.md
+	git add CHANGELOG.md kosmorrolib/__version__.py
 	git commit -m "build: bump version $$RELEASE_NUMBER"
 	git tag "v$$RELEASE_NUMBER"
 	git checkout features