Signed-off-by: Leandro Lucarella <luca-frequenz@llucax.com>

This is to pull a fix for using the correct `protobuf` related
dependencies.

Signed-off-by: Leandro Lucarella <luca-frequenz@llucax.com>

We can't use wide dependencies because otherwise when building the
wheel, the latest version is used, but the generate code should use the
minimum supported version for the generation, not the latest one. See:
https://protobuf.dev/support/cross-version-runtime-guarantee/

Signed-off-by: Leandro Lucarella <luca-frequenz@llucax.com>

This is to avoid an issue with some outdated `griffe` imports.

While upgrading the dependency we need to remove the `custom_templates`
option that we don't use, as it was previously ignored but now the
plugin checks if the directory exists and fails if it doesn't.

Signed-off-by: Leandro Lucarella <luca-frequenz@llucax.com>

It seems like something changed in the dependencies that before we
didn't need to configure `mypy` to be able to find the namespace and to
get the `grpc-stubs` package, but now we do.

Signed-off-by: Leandro Lucarella <luca-frequenz@llucax.com>

We are getting some warnings from MkDocs that are not really important
and it would be hard to fix for this old branch, so we just disable
strict mode for now.

Signed-off-by: Leandro Lucarella <luca-frequenz@llucax.com>

This is a backport of #254 plus a few v0.15 specific fixes to make the
CI pass in this old branch.

- **Bump `frequenz-api-common` submodule to v0.6.2**
- **Pin grpc related dependencies**
- **Bump mkdocstrings dependencies**
- **Fix `mypy` configuration**
- **Stop using strict mode in `mkdocs.yml`**