devcontainer: replace VAULT_HOST with AWS_ROLE_ARN

[jjacobelli]

This PR is replacing the VAULT_HOST variable with AWS_ROLE_ARN. This is required to use the new token service to get AWS credentials.

[jameslamb]

It does look like sccache is working here:

  Compile requests                    322
  Compile requests executed           322
  Cache hits                          317

(build link)

But I don't understand these changes. Is there a write-up about them I could read?

For example, how is this working when there wasn't a corresponding change in https://github.com/rapidsai/devcontainers/commits/branch-24.12/?

Features in these devcontainers explicitly expect to use vault, I thought: https://github.com/rapidsai/devcontainers/blob/a5bba51e0c21e71e90f8b4c63e96a3c3d2dcdd53/USAGE.md?plain=1#L40

[jjacobelli]

But I don't understand these changes. Is there a write-up about them I could read?

I don't think there is an issue that I can link here, but we are working on removing our Vault instance to use our new token service to get AWS credentials instead

For example, how is this working when there wasn't a corresponding change in https://github.com/rapidsai/devcontainers/commits/branch-24.12/?

Features in these devcontainers explicitly expect to use vault, I thought: https://github.com/rapidsai/devcontainers/blob/a5bba51e0c21e71e90f8b4c63e96a3c3d2dcdd53/USAGE.md?plain=1#L40

Changes on devcontainers are done in this PR: rapidsai/devcontainers#392

[bdice]

/merge

[jameslamb]

Ah I see, thanks for the links @jjacobelli (here and the others you sent me privately). Changes make sense to me with that additional context. And thanks @trxcllnt and @bdice for helping with approvals while I was out.