ci: clean up CI workflow

[ClementTsang]

Description

A description of the change and what it does. If relevant (such as any change that modifies the UI), please provide screenshots of the change:

Cleaned up and updated the primary GitHub CI workflow. Also fixes a bug caught during this check.

Testing

Tested by this PR, which should trigger the CI workflow.

Checklist

If relevant, ensure the following have been met:

• Areas your change affects have been linted using rustfmt (cargo fmt)
• The change has been tested and doesn't appear to cause any unintended breakage
• Documentation has been added/updated if needed (README.md, help menu, etc.)
• The pull request passes the provided CI pipeline
• There are no merge conflicts

[codecov-commenter]

Codecov Report

Merging #720 (a92313a) into master (e646a76) will increase coverage by 0.00%.
The diff coverage is 50.00%.

@@           Coverage Diff           @@
##           master     #720   +/-   ##
=======================================
  Coverage   20.78%   20.78%           
=======================================
  Files          53       53           
  Lines       13618    13620    +2     
=======================================
+ Hits         2830     2831    +1     
- Misses      10788    10789    +1     

Impacted Files	Coverage Δ
src/options.rs	61.78% <42.85%> (-0.04%)	⬇️
src/clap.rs	99.68% <100.00%> (ø)

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