Update dependency NuGet.ProjectModel to v6.1.0

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
NuGet.ProjectModel (source)	nuget	minor	6.0.0 -> 6.1.0

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Configuration

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[codecov]

Codecov Report

Merging #619 (d681ec2) into master (b6977cb) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #619   +/-   ##
=======================================
  Coverage   83.14%   83.14%           
=======================================
  Files          16       16           
  Lines         540      540           
  Branches       35       35           
=======================================
  Hits          449      449           
  Misses         91       91           

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