chore: Add Cargo.lock, fix builds on 1.75

[aborgna-q]

icu4x bumped its MSRV to 1.81 for all of it's sub-crates in a minor release. This means that we can no longer build hugr with 1.75.

This PR unignores the Cargo.lock and cargo updates the dependencies to downgrade them to a supported version. We should see the 1.75 CI job fail if dependabot tries to update them again.

This problem is caused by the dependency resolver v2 ignoring the rust-version field in the crates. In rust 2024 the new v3 resolver should be able to use only valid versions, but we have a long way until we are able to use that.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 83.69%. Comparing base (7a9bda5) to head (003357d).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1942   +/-   ##
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  Coverage   83.69%   83.69%           
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  Files         196      196           
  Lines       37691    37691           
  Branches    34504    34504           
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  Hits        31546    31546           
  Misses       4359     4359           
  Partials     1786     1786           

Flag	Coverage Δ
python	92.34% <ø> (ø)
rust	82.89% <ø> (ø)

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