doc: mention release workflow (#12)

* doc: mention release workflow

* Apply suggestions from code review

Author: hf-kklein

README.md

@@ -90,6 +90,12 @@ edifact = await client.bo4e_to_edifact(boney_comb, EdifactFormatVersion.FV2310)
 ## Development
 For development of this library, follow the instructions in our [Python Template Repository](https://github.com/Hochfrequenz/python_template_repository).
 
+### Release (CI/CD)
+
+To release a new version of this library, [create a new release](https://github.com/Hochfrequenz/TransformerBeeClient.py/releases/new) in GitHub.
+Make sure its tag starts with `v` and the version number, e.g. `v1.2.3`.
+Releases are not restricted to the main branch but we prefer them to happen there.
+
 ## Contribute
 You are very welcome to contribute to this template repository by opening a pull request against the main branch.