Disable mkdocs cross-ref to marshmallow

This is required since the latest marshmallow release, until a fix is
available for:
marshmallow-code/marshmallow#2739

Signed-off-by: Sahas Subramanian <sahas.subramanian@proton.me>

Author: shsms

mkdocs.yml

@@ -120,8 +120,8 @@ plugins:
             - https://frequenz-floss.github.io/frequenz-channels-python/v1.1/objects.inv
             - https://frequenz-floss.github.io/frequenz-client-microgrid-python/v0.5/objects.inv
             - https://frequenz-floss.github.io/frequenz-quantities-python/v1/objects.inv
-            - https://lovasoa.github.io/marshmallow_dataclass/html/objects.inv
-            - https://marshmallow.readthedocs.io/en/stable/objects.inv
+            # - https://lovasoa.github.io/marshmallow_dataclass/html/objects.inv
+            # - https://marshmallow.readthedocs.io/en/stable/objects.inv
             - https://networkx.org/documentation/stable/objects.inv
             - https://numpy.org/doc/stable/objects.inv
             - https://typing-extensions.readthedocs.io/en/stable/objects.inv