Dynamic commit message

[netzwerg]

As far as I can tell, the only way to specify a custom commit message is via SBT_GHPAGES_COMMIT_MESSAGE environment variable, right?

I would like to include version information, along the lines of:

ghPagesCommitMessage := s"Deploy $version"

Is this possible with the env based mechanism, i.e. is it possible to set an environment variable from within build.sbt?