Vendor latest mimir-prometheus

[codesome]

What this PR does

Vendors the latest main branch of mimir-prometheus which brings in the support for out of order samples (was merged into main here). This PR only vendors the Prometheus. We will open separate PRs to add out of order support in the main branch here.

Checklist

• Tests updated
• Documentation added
• CHANGELOG.md updated - the order of entries should be [CHANGE], [FEATURE], [ENHANCEMENT], [BUGFIX]

[codesome]

cc @jesusvazquez

[pstibrany]

Updating mimir-prometheus lgtm, but I'm not familiar with OOO code :-(

[pstibrany]

Note that ChunkReader.Chunk method has changed to

	Chunk(ref chunks.Meta) (chunkenc.Chunk, error)

which is incompatible with vendored Thanos code. Unless you can get mimir-prometheus into Thanos, this isn't going to work.

[jesusvazquez]

@pstibrany We just remembered this, it was something we did early in the development and we forgot, we had to fork thanos to change that interface update https://github.com/jesusvazquez/thanos/

We did so based on the version that was vendored from mimir and just changed the interface and the ocurrences. We could keep it updated.

Is there a way we can make the fork work until we can upstream the out of order changes to prometheus and then update thanos?

[codesome]

@pstibrany I have updated the Thanos dependency with https://github.com/jesusvazquez/thanos/commits/out-of-order, which has a 4 line change on top of Thanos commit that we use in Mimir. Once out of order support is upstreamed, and Thanos has vendored it, we will be able to remove this override. Does that sound fine?

[codesome]

I see that we have https://github.com/grafana/thanos, I will make it part of that so that anyone can update it.

[pstibrany]

Thank you.