Tools: Run shellcheck in GitHub Actions CI

[cclauss]

Summary

Related to:

• pre-commit: Detect errors in scripts with shellcheck #32621
• Tools: Print the Artistic Style version in CI #32669

Tools: Run shellcheck in GitHub Actions CI

Classification & Testing (check all that apply and add your own)

• Checked by a human programmer
• Non-functional change
• No-binary change
• Infrastructure change (e.g. unit tests, helper scripts)
• Automated test(s) verify changes (e.g. unit test, autotest)
• Tested manually, description below (e.g. SITL)
• Tested on hardware
• Logs attached
• Logs available on request

Description

Add a shellcheck job to .github/workflows/test_scripts.yml and run that in GitHub Actions.

Sort jobs to make it easier to spot missing jobs and nearly impossible to add duplicates.

Use the current Python for the performance enhancements in CI.

How was this tested?

Compare the results of:
% find . -path ./modules -prune -o -type f -name '*.sh' -exec shellcheck --severity=error '{}' +
% CI_BUILD_TARGET=shellcheck Tools/scripts/build_ci.sh
to make sure that they match while making changes to the config file .shellcheckrc.

[peterbarker]

CI must pass; Looks like we need to exclude the modules...

But otherwise, quite in favour.

[peterbarker]

How is any of this executed?

The script is run with set -ex which should mean you never get into this block (and all of the other test types seem to rely on this)

[cclauss]

sudo apt-get update && sudo apt-get install --yes shellcheck was adding 5 seconds to every run, so only do that
if: matrix.config == 'shellcheck'

[peterbarker]

LGTM

[peterbarker]

Please avoid patches unrelated to the PR topic,as good as they might be.