fix: allow custom git domains

[koshilki]

Fix for #80

[salesforce-cla]

Thanks for the contribution! Before we can merge this, we need @koshilki to sign the Salesforce.com Contributor License Agreement.

[jdx]

those URLs won't necessarily work on any host so it's better to not display anything than show a broken link

[koshilki]

Thanks for reply, @jdxcode!
I believe URLs would work in most cases, especially using repositoryPrefix configuration, where you can override URL template.
Maybe, as a compromise, we can assume that if repositoryPrefix is present, it means developer knows what he or she is doing, and display link regardless if it's github, gitlab or whatever?
If that's okay, I'll update PR

[jdx]

I'm happy with adding repositoryPrefix as an optional config. I think that's a great solution

[koshilki]

@jdxcode, sorry for a late reaction! I pushed new change to this PR, please take a look

[jdx]

nice job! thanks!

[rhwood]

Is there a sense of when this will be released?

I have a Lerna-based project where the links are all incorrect because oclif-dev readme assumes its running in the root of the git working copy, but its actually running in a subdirectory. It seems to me that the repositoryPrefix config would solve my problem.