fix: update Nimble hash for new Nim version

[crStiv]

Changes

• Updated Nimble hash in nix/nimble.nix to match current Nim version
• Added CI workflow to automatically verify hash when nimble.nix is modified

Details

• Fixed incorrect hash in nix/nimble.nix:

  -   hash = "sha256-sa0irAZjQRZLduEMBPf7sHlY1FigBJTR/vIH4ihii/w=";
  +   hash = "sha256-MVHf19UbOWk8Zba2scj06PxdYYOJA6OXrVyDQ9Ku6Us=";

• Added new workflow .github/workflows/check-nim-hash.yml for automatic hash verification on future updates

Related issues

Fixes #6765

Testing

• Verified locally using nix-build nix/nimble.nix
• CI workflow successfully verifies hash correctness

[tersec]

Overtaken by events: #6795

[crStiv]

Overtaken by events: #6795

but why the issue still opened then?

[tersec]

Overtaken by events: #6795

but why the issue still opened then?

1. it is closed now by the issue reporter
2. I asked the issue reporter, in said issue where it was publicly visible, if the Nim 2.0.14 PR fixed it for them five hours before you opened this PR
3. that said, your .github/workflows/check-nim-hash.yml workflow is interesting, but probably not how we'd prefer to have such functionality. in theory https://github.com/status-im/nimbus-eth2/blob/unstable/ci/nix.Jenkinsfile already should have caught this -- the question is why it didn't. I suspect it's related to Nix's package caching by hash and that it might need to clear that cache first, otherwise it doesn't bother downloading Nimble from GitHub at all.

[jakubgs]

Fixed in alongside some other Nix related issues:

• fix loading Nix Flake shell via direnv, update readme #6807

[tersec]

Resolved in various other ways.