add packages lockfile

[rkm]

Proposed Changes

Adds package restores using a lockfile.

This shouldn't be merged until Dependabot is aware of the lockfile format (dependabot/dependabot-core#1303 and dependabot/dependabot-core#9678)

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New Feature (non-breaking change which adds functionality)
• Breaking Change (fix or feature that would cause existing functionality to not work as expected)
• Documentation-Only Update (if none of the other choices apply)
  • In this case, ensure that the message of the head commit from the source branch is prefixed with [skip ci]

Checklist

By opening this PR, I confirm that I have:

• Reviewed the contributing guidelines for this repository
• Ensured that the PR branch is in sync with the target branch (i.e. it is automatically merge-able)
• Updated any relevant API documentation
• Created or updated any tests if relevant
• Created a news file
  • NOTE: This must include any changes to any of the following files: default.yaml, any of the RabbitMQ server configurations, GlobalOptions.cs
• Listed myself in the CONTRIBUTORS file 🚀
• Requested a review by the @SMI/Reviewers team

Issues

N/A.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 64.81%. Comparing base (83dc691) to head (525514c).
Report is 5 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1875   +/-   ##
=======================================
  Coverage   64.81%   64.81%           
=======================================
  Files         183      183           
  Lines        6554     6554           
  Branches      963      963           
=======================================
  Hits         4248     4248           
  Misses       2020     2020           
  Partials      286      286           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[rkm]

dependabot-core is now aware of lockfiles, however the GitHub app hasn't been updated yet. Tracking this in https://github.com/rkm/dependabot-nuget-lockfile-test

[rkm]

Looks like the dependabot bug has been fixed now, so this PR can proceed