Specify alternate versions

[devth]

Need to be able to specify latest as is the Docker convention.

[a1exsh]

It would be nice to be able to override the version from the command line, in order to use together with CI/CD, e.g:

lein docker build cd${BUILD_NUMBER}

I wonder if anyone is using this already or have found a workaround?

[chrisbetz]

See PRs #5 and #6. You could use our fork [gorillalabs/lein-docker "1.3.0"] with the contribution from #6 .