Support version locking `<=` and not just overwrite with `=`

It looks like during the promotion of a cookbook the version and constraint are written out without regard to a possibly different relationship. Could this simply update the version and not the constraint or have it as a possible option? It would be very helpful for us, but I am not sure which path makes more sense to you.

The specific line writing this out is:

knife-spork/lib/chef/knife/spork-promote.rb

Line 80 in 6606c22

environment.cookbook_versions[cookbook] = "= #{new_version}"

Thanks!

@masteinhauser it would definitely be possible to preserve the existing constraint operator if a different one exists, although it isn't something we've ever had a requirement for, since we always use the "=" operator. That said, it's definitely something I would consider adding.

I can look at this for a future version, or will happily look at pull requests adding this :)

@masteinhauser provisionally added this to the milestone for the next release (1.3.3)

Released in latest version, closing