ci: docker "toomanyrequests: You have reached your pull rate limit"

The "build-repro-linux", "build-repro-windows", and "build-repro-macos" jobs are currently failing with the error "toomanyrequests: You have reached your pull rate limit":

Running with gitlab-runner 17.3.1 (66269445)
  on ci-runner-x86-03-main 1yUAFT6R, system ID: s_2018d3279691
  feature flags: FF_NETWORK_PER_BUILD:true, FF_DISABLE_UMASK_FOR_DOCKER_EXECUTOR:true
Preparing the "docker" executor 04:23
Using Docker executor with image amd64/rust:1.76.0-alpine3.18 ...
Pulling docker image amd64/rust:1.76.0-alpine3.18 ...
WARNING: Failed to pull image with policy "always": initializing source docker://amd64/rust:1.76.0-alpine3.18: reading manifest 1.76.0-alpine3.18 in docker.io/amd64/rust: toomanyrequests: You have reached your pull rate limit. You may increase the limit by authenticating and upgrading: https://www.docker.com/increase-rate-limit (manager.go:251:126s)
Attempt #2: Trying "if-not-present" pull policy
Pulling docker image amd64/rust:1.76.0-alpine3.18 ...
WARNING: Failed to pull image with policy "if-not-present": initializing source docker://amd64/rust:1.76.0-alpine3.18: reading manifest 1.76.0-alpine3.18 in docker.io/amd64/rust: toomanyrequests: You have reached your pull rate limit. You may increase the limit by authenticating and upgrading: https://www.docker.com/increase-rate-limit (manager.go:251:133s)
ERROR: Job failed: failed to pull image "amd64/rust:1.76.0-alpine3.18" with specified policies [always if-not-present]: initializing source docker://amd64/rust:1.76.0-alpine3.18: reading manifest 1.76.0-alpine3.18 in docker.io/amd64/rust: toomanyrequests: You have reached your pull rate limit. You may increase the limit by authenticating and upgrading: https://www.docker.com/increase-rate-limit (manager.go:251:133s)

I'm not sure how Tor's CI is set up, but it would probably be good to either cache docker images or use a repo with much higher rate limits. Otherwise the IP of the CI runner will be rate limited.

This issue will probably go away in a few hours or so, but it would be nice to have a better workaround so that it doesn't happen in the future.