Disable SSL by default

The microgrid API does not use SSL by default, so it makes sense to
disable it by default in the client. This was the behavior in previous
versions and it was changed by mistake in a previous commit.

Also prepare the release notes for the next patch release.

Signed-off-by: Leandro Lucarella <[email protected]>

Author: llucax

RELEASE_NOTES.md

@@ -1,17 +1,5 @@
 # Frequenz Microgrid API Client Release Notes
 
-## Summary
-
-<!-- Here goes a general summary of what this release is about -->
-
-## Upgrading
-
-<!-- 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 -->
+- Fix a bug where SSL was enabled by default. It is now disabled by default as in previous versions.

src/frequenz/client/microgrid/_client.py

@@ -6,6 +6,7 @@
 import asyncio
 import logging
 from collections.abc import AsyncIterator, Awaitable, Callable, Iterable, Set
+from dataclasses import replace
 from typing import Any, TypeVar, cast
 
 import grpc.aio
@@ -44,13 +45,24 @@
 _logger = logging.getLogger(__name__)
 
 
+DEFAULT_CHANNEL_OPTIONS = replace(
+    channel.ChannelOptions(), ssl=channel.SslOptions(enabled=False)
+)
+"""The default channel options for the microgrid API client.
+
+These are the same defaults as the common default options but with SSL disabled, as the
+microgrid API does not use SSL by default.
+"""
+
+
 class ApiClient:
     """A microgrid API client."""
 
     def __init__(
         self,
         server_url: str,
         *,
+        channel_options: channel.ChannelOptions = DEFAULT_CHANNEL_OPTIONS,
         retry_strategy: retry.Strategy | None = None,
     ) -> None:
         """Initialize the class instance.
@@ -62,14 +74,18 @@ def __init__(
                 where the `port` should be an int between 0 and 65535 (defaulting to
                 9090) and `ssl` should be a boolean (defaulting to `false`).
                 For example: `grpc://localhost:1090?ssl=true`.
+            channel_options: The default options use to create the channel when not
+                specified in the URL.
             retry_strategy: The retry strategy to use to reconnect when the connection
                 to the streaming method is lost. By default a linear backoff strategy
                 is used.
         """
         self._server_url = server_url
         """The location of the microgrid API server as a URL."""
 
-        self.api = microgrid_pb2_grpc.MicrogridStub(channel.parse_grpc_uri(server_url))
+        self.api = microgrid_pb2_grpc.MicrogridStub(
+            channel.parse_grpc_uri(server_url, defaults=channel_options)
+        )
         """The gRPC stub for the microgrid API."""
 
         self._broadcasters: dict[int, streaming.GrpcStreamBroadcaster[Any, Any]] = {}