v1.18: ci: ignore curve25519-dalek audit temporarily (backport of #1786)

[mergify]

Problem

audit failed

I had a PR for this one weeks ago, but it's still stuck in the SPL downstream project test. I will prioritize this one. Ignore this audit to unblock CI.

#1693

Summary of Changes

ignore the audit temporarily

---

This is an automatic backport of pull request #1786 done by Mergify.

[mergify]

Cherry-pick of a6bc917 has failed:

On branch mergify/bp/v1.18/pr-1786
Your branch is up to date with 'origin/v1.18'.

You are currently cherry-picking commit a6bc917f36.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   ci/do-audit.sh

no changes added to commit (use "git add" and/or "git commit -a")

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[steviez]

I know we ignored the audit on master because we expect to perform the suggested version bump soon; however, it is not immediately obvious to me if ignoring the issue is safe on our v1.18 branch. @ryoqun - You reviewed the initial PR, do you have any insights on this? If not, I can do digging through to try to figure out what the appropriate action is for the v1.18 branch

[yihau]

or we can use https://github.com/anza-xyz/curve25519-dalek/commits/3.2.1-fix-audit instead

[steviez]

Closing this PR - we ended up getting this as part of #1939