Allow passing env vars to verifiable build container

[riordanp]

No description provided.

[vercel]

@riordanp is attempting to deploy a commit to the coral-xyz Team on Vercel.

A member of the Team first needs to authorize it.

[Henry-E]

Is there much else you still want to add to this PR? It looks pretty reasonable to add.

Also

• don't forget to run cargo fmt
• please add a note to the changelog as well

[riordanp]

Should be ready now

[Henry-E]

Looks like a clippy lint still needs to be satisfied or excepted somehow. https://github.com/coral-xyz/anchor/actions/runs/3742902170/jobs/6354794762

Also it's weird the changelog isn't registering as a merge conflict because it looks like you don't have version of the changelog in which 0.26.0 has already been released (we launched it last week). So your change should be the first new feature in the unreleased version. Sorry to be anal about the changelog stuff but it's just hard for me to rebase your repo / update the changelog manually when it's out of sync.