Fix TagBot workflow

[omus]

Discovered that the TagBot workflow is broken: https://github.com/JuliaTesting/ExprTools.jl/actions/runs/31789383577/job/94732625230. Turns out we need to use ubuntu-latest to support containers: https://github.com/JuliaRegistries/TagBot/blob/56ed3aa6e43dd7b4b6e652b0b09218674a098f23/example.yml#L14

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.41%. Comparing base (f650f43) to head (022b12e).

Additional details and impacted files

@@           Coverage Diff           @@
##           master      #55   +/-   ##
=======================================
  Coverage   97.41%   97.41%           
=======================================
  Files           6        6           
  Lines         232      232           
=======================================
  Hits          226      226           
  Misses          6        6           

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[omus]

Proof this is now fixed: https://github.com/JuliaTesting/ExprTools.jl/actions/runs/31789915789/job/94734279889

[omus]

I don't have the necessary access to this repo to fix the SSH deploy key

[omus]

These changes are still valid and can be merged but it won't work until the SSH key is fixed