Variables with default values don't work for image tags

[flcdrg]

Trying to use {env.VERSION:v1.0} (or anything else for the default value) results in an error.

[ERROR] failed to load config from "dobi.yaml": Error at myimage.tags: failed validation: the first tag "v1.0}" may not include an image name

I'm guessing it's trying to validate the tag before the variable is evaluated.

[dnephin]

Thank you for the bug report!

One way to fix this might be to have ValidateTags create a call something like this https://github.com/dnephin/dobi/blob/master/execenv/environment.go#L45-L51 on the tag value, before parsing it, to remove the template.