Feature/git tag semver

Please have a look at this PR to add support for git url with valid semver tags.

This is what we discussed in issue #3 :)
Yes, there is a check but if the check fails you error which would mean that having `git+ssh://git@git.example.com:b/b.git#various-changes` in package.json as a Git version would make `check-dependencies` always fail.