Azure-cli: az image: allow to add tags to existing image

[jstodola]

Is your feature request related to a problem? Please describe.
It's not possible to add a tag to an existing image using azure-cli. The "image update" command doesn't exist in azure-cli-2.0.56-1.el7

Describe the solution you'd like
az image update --name $IMAGE_NAME --resource-group $RESOURCE_GROUP --set "tags.$MY_TAG=$VALUE"

Additional context
"az image create" allows to add tags when creating a new image, however this solution doesn't work for me, since I need to be able to tag both new and existing images.

[tjprescott]

Great point, @jstodola!

In the meantime, you could try the following commands:
az resource tag This seems more relevant to your current needs
az resource update If you need more powerful updating capability

[jstodola]

Thanks for the hint, @tjprescott , it works for my needs.