Remove sybil from mypy overrides

The new sybil version (6.0.0) provides type hints, so the overrides are
not needed anymore.

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

Author: llucax

pyproject.toml

@@ -161,7 +161,7 @@ packages = ["frequenz.client.base"]
 strict = true
 
 [[tool.mypy.overrides]]
-module = ["mkdocs_macros.*", "sybil", "sybil.*"]
+module = ["mkdocs_macros.*"]
 ignore_missing_imports = true
 
 [tool.setuptools_scm]