ci: try using GHA instead of Cirrus for FreeBSD in basic CI

[ClementTsang]

Description

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Ideally we minimize our usage of Cirrus CI, especially for typical PR CI workflows, since it's a bit cludgy to work with. This method is also more extendable to things like OpenBSD. After this PR, we no longer should be using Cirrus anywhere in our default workflow except for deploys.

On that note, at least for now, I guess it's fine for deploys since that's not super frequent and at this point I have that working fairly well when automated + I don't usually have to wait for it, as opposed to PRs where I may commit many times.

Issue

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Closes: #

Testing

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• Windows
• macOS
• Linux

Checklist

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• 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, doc pages, etc.)
• The pull request passes the provided CI pipeline
• There are no merge conflicts
• If relevant, new tests were added (don't worry too much about coverage)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 41.65%. Comparing base (7c35def) to head (f3a7ecd).
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1577      +/-   ##
==========================================
+ Coverage   41.63%   41.65%   +0.01%     
==========================================
  Files         114      114              
  Lines       17893    17893              
==========================================
+ Hits         7450     7453       +3     
+ Misses      10443    10440       -3     

Flag	Coverage Δ
macos-12	36.94% <ø> (ø)
ubuntu-latest	43.38% <ø> (+0.01%)	⬆️
windows-2019	36.87% <ø> (ø)

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