fix(ci): Build zebrad with Rust 1.63 to avoid Zcash parameter download hangs

[teor2345]

Motivation

Zcash parameter downloads hang when built with Rust 1.64.

Solution

• Use Rust 1.63 instead of Rust stable in the zebrad GitHub Actions workflows and Dockerfiles
• Change the branch protection rules to require 1.63 instead of stable

Review

This is urgent because it blocks merging everything else.

Reviewer Checklist

• Will the PR name make sense to users?
  • Does it need extra CHANGELOG info? (new features, breaking changes, large changes)
• Are the PR labels correct?
• Does the code do what the ticket and PR says?
• How do you know it works? Does it have tests?

[teor2345]

I'm also running the Docker Zcash parameter download here, to see if it is impacted:
https://github.com/ZcashFoundation/zebra/actions/runs/3123995445

[codecov]

Codecov Report

Merging #5251 (347d79b) into main (d8b0481) will decrease coverage by 0.06%.
The diff coverage is n/a.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5251      +/-   ##
==========================================
- Coverage   79.17%   79.11%   -0.07%     
==========================================
  Files         307      307              
  Lines       39225    39225              
==========================================
- Hits        31058    31032      -26     
- Misses       8167     8193      +26     

[teor2345]

Using:

$ rustc -vV
rustc 1.66.0-nightly (9062b780b 2022-09-21)
binary: rustc
commit-hash: 9062b780b32d2eab060b4432863e085d9504ca5c
commit-date: 2022-09-21
host: x86_64-unknown-linux-gnu
release: 1.66.0-nightly
LLVM version: 15.0.0

I get these logs:

$ mv ~/.zcash-params ~/.zcash-params-old
$ cargo run download
    Finished dev [optimized + debuginfo] target(s) in 0.49s
     Running `target/debug/zebrad download`
2022-09-26T02:21:28.423433Z  INFO zebrad::components::tracing::component: started tracing component filter="info" TRACING_STATIC_MAX_LEVEL=LevelFilter::TRACE LOG_STATIC_MAX_LEVEL=Trace
2022-09-26T02:21:28.423473Z  INFO {zebrad="2465f4b" net="Main"}: zebrad::application: initialized rayon thread pool for CPU-bound tasks num_threads=36
2022-09-26T02:21:28.423490Z  INFO {zebrad="2465f4b" net="Main"}: zebrad::commands::download: checking if Zcash Sapling and Sprout parameters have been downloaded
2022-09-26T02:21:28.423536Z  INFO {zebrad="2465f4b" net="Main"}: zebra_consensus::primitives::groth16::params: downloading Zcash Sapling parameters
2022-09-26T02:35:30.407524Z  INFO {zebrad="2465f4b" net="Main"}: zebra_consensus::primitives::groth16::params: downloading Zcash Sprout parameters
2022-09-26T03:35:30.410102Z  INFO {zebrad="2465f4b" net="Main"}: zebra_consensus::primitives::groth16::params: error downloading Zcash Sprout parameters, retrying error=IoError(Custom { kind: Other, error: "sprout-groth16.params failed reading:\nexpected: 725523612 bytes,\nactual:   211288196 bytes from \"https://download.z.cash/downloads/sprout-groth16.params.part.1 + https://download.z.cash/downloads/sprout-groth16.params.part.2\",\nerror: Custom { kind: Other, error: \"download response failed: IoError(Custom { kind: TimedOut, error: \\\"the timeout of the request was reached\\\" })\" }" })

[upbqdn]

All changes are correct, and CI passes, so I'm approving.

[mpguerra]

Should #5091 be closed then?

[teor2345]

Should #5091 be closed then?

No, this PR is a temporary workaround to use Rust 1.63, which is currently unsupported.

That ticket is about Rust 1.64, which we will have to upgrade to eventually.
We need to stay on a supported version of Rust, because our dependencies could stop supporting Rust 1.63 at any time.