Trigger Lagoon deployments based on Git tags.

Adding a sensible, rules-based tag deployment process to Lagoon. We could potentially envision it working similarly to the “promote” workflow, triggered by a specific tag pattern (likely via regex), tag placement (i.e on a configured branch), and tag age (tags on older commits would require careful handling).

We agree that the addition of tag-based deployments would provide more flexibility in Git workflows, but would need careful design consideration prior to implementation.