Changelog adjusted

Changelog.md

@@ -1,3 +1,8 @@
+# TODO 0.12.2 / 0.13
+- internal improvements
+  - code formatting/style 
+  - sensible style checks as optional CI job
+
 # 0.12.1
 - `TagType`-enum introduced in `v0.11` is now actually public
 - internal code improvements