Suppress progress bar in CI

[rotu]

In CI, pip shows the progress bar https://ci.ros2.org/job/ci_linux/lastStableBuild/consoleText

This creates log noise and should probably be disabled (maybe with --progress-bar off or --quiet) This can be set with pip config https://pip.pypa.io/en/stable/reference/pip_config/

  Downloading mypy-0.770-cp38-cp38-manylinux1_x86_64.whl (22.6 MB)
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[rotu]

Hmm... locally it seems to suppress the progress bar by default if I pipe the output of pip. So maybe this is because we're telling the script to use a pty which is tricking pip to use interactive output. Unfortunately, I don't see a way to enable colors for pip if run from a non-shell, just disable colors if run from a shell.

[hidmic]

Current consensus is to, ideally, find a way to reduce pip's verbosity without dropping all user feedback i.e. a blocking, quiet execution is undesirable.