Fix goreleaser config for setting version number

[jhump]

This isn't a real issue in practice since the default value of the var should be correct. This configuration for goreleaser is only in place in the off-chance that we tag a sha where the var has not been correctly updated. In that case, both make install and goreleaser will update the var so the built binary emits the correct version.

This was using the wrong package because I forgot to update this config in #37, when this var was moved out of the main package into an internal app package.