Bump NuGet.ProjectModel from 6.13.1 to 7.6.0

---
updated-dependencies:
- dependency-name: NuGet.ProjectModel
  dependency-version: 7.6.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

src/Directory.Packages.props

@@ -5,7 +5,7 @@
     <PackageVersion Include="Mono.Options" Version="6.12.0.148" />
     <PackageVersion Include="NuGetizer" Version="1.2.4" />
     <PackageVersion Include="Microsoft.Extensions.DependencyModel" Version="9.0.2" />
-    <PackageVersion Include="NuGet.ProjectModel" Version="6.13.1" />
+    <PackageVersion Include="NuGet.ProjectModel" Version="7.6.0" />
     <PackageVersion Include="Spectre.Console" Version="0.49.1" />
     <PackageVersion Include="Spectre.Console.Analyzer" Version="1.0.0" />
     <PackageVersion Include="ThisAssembly.Project" Version="1.2.15" />