Support shallow depth checkout

[mbrancato]

Description

When the "load git source" internal step runs when this action is used, it fetches the full depth of git tags. Is there a way to set a smaller depth? e.g. depth=1

This is the step I'm referring to, which will start listing off hundreds if not thousands of tags.

https://github.com/docker/docs/blob/e20141cba1746fa824c47b2b4aab300b0e3ed85c/content/manuals/build/bake/remote-definition.md?plain=1#L9-L16

[crazy-max]

It's depth=1 without tags if ref is not a commit sha in BuildKit atm: https://github.com/moby/buildkit/blob/7e2b28d03286206d3bee5f9fd2517b78b072f878/source/git/source.go#L482-L484

@tonistiigi Do you think we could have an opt-in to fetch with depth 1 without tags?