fix: Automate MSRV lockfile updates

[day01]

Motivation

update Cargo.lock.MSRV automatically in release-plz pull requests - doesnt work

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.67%. Comparing base (9d33d0e) to head (06a2030).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #398   +/-   ##
=======================================
  Coverage   94.67%   94.67%           
=======================================
  Files          61       61           
  Lines       13322    13322           
=======================================
  Hits        12613    12613           
  Misses        709      709           

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[YeungOnion]

When this works, will it be that the MSRV file will be updated each time this action runs? Or will it be something else?

[day01]

Will be updated when action triggered. It regenerates Cargo.lock.MSRV, but commits and pushes it only if the file actually changed

if git diff --quiet -- Cargo.lock.MSRV; then
    exit 0
fi