chore: bump NuGet.PackageManagement from 6.6.0 to 6.6.1 in /src

Bumps [NuGet.PackageManagement](https://github.com/NuGet/NuGet.Client) from 6.6.0 to 6.6.1.
- [Release notes](https://github.com/NuGet/NuGet.Client/releases)
- [Commits](https://github.com/NuGet/NuGet.Client/commits)

---
updated-dependencies:
- dependency-name: NuGet.PackageManagement
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

src/UnityNuGet/UnityNuGet.csproj

@@ -23,7 +23,7 @@
 
     <ItemGroup>
       <PackageReference Include="Microsoft.Extensions.Options" Version="7.0.1" />
-      <PackageReference Include="NuGet.PackageManagement" Version="6.6.0" />
+      <PackageReference Include="NuGet.PackageManagement" Version="6.6.1" />
       <PackageReference Include="Microsoft.Extensions.Caching.Memory" Version="7.0.0" /> 
       <PackageReference Include="NUglify" Version="1.20.7" /> 
       <PackageReference Include="Scriban" Version="5.7.0" />