Bump NuGet.Protocol from 6.5.0 to 6.6.1 (#966)

Bumps NuGet.Protocol from 6.5.0 to 6.6.1.

---
updated-dependencies:
- dependency-name: NuGet.Protocol
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Directory.Packages.props

@@ -26,7 +26,7 @@
     <PackageVersion Include="Microsoft.Windows.SDK.Win32Docs" Version="$(ApiDocsVersion)" />
     <PackageVersion Include="Microsoft.Windows.SDK.Win32Metadata" Version="$(MetadataVersion)" />
     <PackageVersion Include="Microsoft.Windows.WDK.Win32Metadata" Version="$(WDKMetadataVersion)" />
-    <PackageVersion Include="NuGet.Protocol" Version="6.5.0" />
+    <PackageVersion Include="NuGet.Protocol" Version="6.6.1" />
     <PackageVersion Include="System.Collections.Immutable" Version="6.0.0" />
     <PackageVersion Include="System.Memory" Version="4.5.5" />
     <PackageVersion Include="System.Reflection.Metadata" Version="6.0.1" />