Workbench: Remove Chalice.

It's conflicting with Black (require conflicting versions of Click) and
I don't remember the last time I used Chalice (if ever) but I do use
Black often.

workbench/Dockerfile

@@ -172,7 +172,6 @@ RUN apt-get update && \
         boto \
         boto3 \
         bump2version \
-        chalice \
         check-manifest \
         colorama \
         cookiecutter \