Provide a way to resolve commit SHA1 from tag refs

Right now, resolveRef({ ref: '1.0.0' }) will not return the commit SHA1 associated to the tag 1.0.0 but the object id of the tag.

I need a way to use resolveRef and retrieve the commit SHA1 if it’s a tag. I think I saw somewhere that this process is called peeling.

Something like this would be awesome:

const tagObjectId = await resolveRef({ ref: '1.0.0' })
const tagCommitId = await resolveRef({ ref: '1.0.0', peelTag: true })

WDYT?

[wmhilton]

I’ve started working on this! I got the code done, but adding all the tests for 8 new commands is super tedious. 😃

[wmhilton]

A nice thing about doing it this way is we avoid introducing the term “peel”. AFAICT it’s pretty obscure… being mentioned only briefly once in the user documentation, and referred to 2 times in the technical documentation. It’s never actually defined anywhere except in stack overflow.