Use file based signer now that Rekor supports it.

[vaikas]

Signed-off-by: Ville Aikas vaikas@chainguard.dev

Summary

Now that Rekor supports file based signing key, use that so any Rekor restart won't screw everything up by creating a new key.
This was added here:
sigstore/rekor#1049
Since there hasn't been a Rekor release since, we choose the one that was created by CI build to get the tests going using this.

Release Note

Use file based signing key for Rekor.

Documentation

Updated the README.

[vaikas]

Hrm, did I bring the wrong verrsion of rekor 😭

  2022-09-16T04:05:09.065Z  ERROR  app/root.go:53  unknown flag: --rekor_server.signer-pwd
  github.com/sigstore/rekor/cmd/rekor-server/app.Execute
    github.com/sigstore/rekor/cmd/rekor-server/app/root.go:53
  main.main
    github.com/sigstore/rekor/cmd/rekor-server/main.go:21
  runtime.main
    runtime/proc.go:250

[vaikas]

I might have, but I also specified the wrong freaking flag name. Getting late 🤣