Windows build boot failure Unable to open agent private key path...

[IanButterworth]

This has been happening for a long time but I couldn't find an issue.

https://buildkite.com/julialang/julia-master/builds/46074#0195bab7-6fb8-4b79-b321-87ec7a7c2acb

Running global environment hook | 0s
-- | --
  | > C:\buildkite-agent\hooks\environment
  | -> source C:\buildkite-agent\hooks/environment.d/100_gr_env.sh
  | -> source C:\buildkite-agent\hooks/environment.d/101_julia_num_cores.sh
  | -> source C:\buildkite-agent\hooks/environment.d/500_windows_debugging.sh
  | -> source C:\buildkite-agent\hooks/environment.d/999_cryptic_unlock.sh
  | ERROR: Unable to open agent private key path 'C:\secrets/agent.key'!  Make sure your agent has this file deployed within it!
  | 🚨 Error: Error setting up bootstrap: The global environment hook exited with status 1

The code is here
https://github.com/JuliaCI/cryptic-buildkite-plugin/blob/f15c1a15fe5baaca30037e149776a74fff25d8ac/hooks/environment.agent#L75

[IanButterworth]

I'll keep this issue open for visibility but there's one open already here JuliaCI/sandboxed-buildkite-agent#42