chore(rootfs/Dockerfile): update Azure CLI to 2.1.0 (#218)

See https://github.com/MicrosoftDocs/azure-docs-cli/blob/master/docs-ref-conceptual/release-notes-azure-cli.md#february-18-2020

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=2.0.80 \
+ENV AZCLI_VERSION=2.1.0 \
     DOCKER_VERSION=19.03.4 \
     GO_VERSION=1.13.6 \
     GLIDE_VERSION=v0.13.3 \