Exclude new buggy version of imageio.
See
BytesIO no longer work due to omission in refactor.
@@ -42,7 +42,7 @@ install_requires =
cachey>=0.2.1
certifi>=2018.1.18
dask[array]>=2.15.0,!=2.28.0 # https://github.com/napari/napari/issues/1656
- imageio>=2.5.0
+ imageio>=2.5.0,!=2.11.0
importlib-metadata>=1.5.0 ; python_version < '3.8'
jsonschema>=3.2.0
magicgui>=0.3.3
