chore(rootfs/Dockerfile): update Azure CLI to 2.10.1 (#245)

See https://docs.microsoft.com/en-us/cli/azure/release-notes-azure-cli?view=azure-cli-latest&tabs=azure-cli#august-11-2020

Author: mboersma

rootfs/Dockerfile

@@ -3,7 +3,7 @@ FROM ubuntu:18.04
 LABEL name="deis-go-dev" \
       maintainer="Matt Boersma <matt.boersma@microsoft.com>"
 
-ENV AZCLI_VERSION=2.9.1 \
+ENV AZCLI_VERSION=2.10.1 \
     DOCKER_VERSION=19.03.4 \
     GO_VERSION=1.15rc2 \
     GLIDE_VERSION=v0.13.3 \