Clear release notes

RELEASE_NOTES.md

@@ -1,60 +1,17 @@
 # Frequenz Client Base Library Release Notes
 
+## Summary
+
+<!-- Here goes a general summary of what this release is about -->
+
 ## Upgrading
 
-The `BaseApiClient` class is generic again. There was too many issues with the new approach, so it was rolled back.
-
-- If you are upgrading from v0.7.x, you should be able to roll back your changes with the upgrade and just keep the new `stub` property.
-
-    ```python
-   # Old
-   from __future__ import annotations
-   import my_service_pb2_grpc
-   class MyApiClient(BaseApiClient):
-       def __init__(self, server_url: str, *, ...) -> None:
-           super().__init__(server_url, ...)
-           stub = my_service_pb2_grpc.MyServiceStub(self.channel)
-           self._stub: my_service_pb2_grpc.MyServiceAsyncStub = stub  # type: ignore
-           ...
-
-       @property
-       def stub(self) -> my_service_pb2_grpc.MyServiceAsyncStub:
-           if self.channel is None:
-               raise ClientNotConnected(server_url=self.server_url, operation="stub")
-           return self._stub
-
-   # New
-   from __future__ import annotations
-   import my_service_pb2_grpc
-   from my_service_pb2_grpc import MyServiceStub
-   class MyApiClient(BaseApiClient[MyServiceStub]):
-       def __init__(self, server_url: str, *, ...) -> None:
-           super().__init__(server_url, MyServiceStub, ...)
-           ...
-
-       @property
-       def stub(self) -> my_service_pb2_grpc.MyServiceAsyncStub:
-           """The gRPC stub for the API."""
-           if self.channel is None or self._stub is None:
-               raise ClientNotConnected(server_url=self.server_url, operation="stub")
-           # This type: ignore is needed because we need to cast the sync stub to
-           # the async stub, but we can't use cast because the async stub doesn't
-           # actually exists to the eyes of the interpreter, it only exists for the
-           # type-checker, so it can only be used for type hints.
-           return self._stub  # type: ignore
-   ```
-
-- If you are upgrading from v0.6.x, you should only need to add the `stub` property to your client class and then use that property instead of `_stub` in your code.
-
-    ```python
-       @property
-       def stub(self) -> my_service_pb2_grpc.MyServiceAsyncStub:
-           """The gRPC stub for the API."""
-           if self.channel is None or self._stub is None:
-               raise ClientNotConnected(server_url=self.server_url, operation="stub")
-           # This type: ignore is needed because we need to cast the sync stub to
-           # the async stub, but we can't use cast because the async stub doesn't
-           # actually exists to the eyes of the interpreter, it only exists for the
-           # type-checker, so it can only be used for type hints.
-           return self._stub  # type: ignore
-   ```
+<!-- Here goes notes on how to upgrade from previous versions, including deprecations and what they should be replaced with -->
+
+## New Features
+
+<!-- Here goes the main new features and examples or instructions on how to use them -->
+
+## Bug Fixes
+
+<!-- Here goes notable bug fixes that are worth a special mention or explanation -->