Support Git tags as well as branches

[lpeabody]

There doesn't seem to be any support for running ci-agent against tags. Branches are good but being able to build a sandbox based off a tag would be extremely helpful.

I have some thoughts around how I would do this, based on existing convention set in the project's code. Before I get started with it however, I'm wondering:

1. Was there a specific reason tags aren't supported?
2. If a previous attempt was made to include support for tagging, what were the difficulties surrounding it's implementation that inevitably lead to the feature not being supported?

Asking just so I know what issues I can expect to run into.

EDIT: It's probably worth mentioning this issue arises from a Bitbucket Pipelines project. It's possible this is a specific issue with Bitbucket. I have not used CI Agent on other systems.

[lmakarov]

@lpeabody git tags are generally used in production to tag and deploy releases, while sandboxes are focused on the non-prod / development workflow using branches.

However, I have to admit, that I've seen git workflows, where tags are utilized for every build and deployments to non-prod environments. Considering that, it won't hurt to add support for tags.

If we introduce support for tags, it will need to be implemented for all supported configurations:

• Bitbucket Pipelines + Bitbucket
• CircleCI + Github
• CircleCI + Bitbucket
• GitLabCI + GitLab