Move to latest NuGet.exe (#23786)

* Move to latest NuGet.exe
- 5.3.0 -> 5.6.0
- should improve performance and may improve reliability

* Also switch from NuGet.Build.Tasks to NuGet.Packaging
- move to 5.6.0 version here too
- reduce transitive dependencies; we don't need them all

eng/tools/RepoTasks/RepoTasks.csproj

@@ -12,7 +12,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="NuGet.Build.Tasks" Version="5.3.0" />
+    <PackageReference Include="NuGet.Packaging" Version="5.6.0" />
     <PackageReference Include="Microsoft.Extensions.DependencyModel" Version="2.1.0" />
   </ItemGroup>
 

src/Installers/Windows/GenerateNugetPackageWithMsi.ps1

@@ -25,9 +25,8 @@ if (-not (Test-Path $NuGetDir)) {
 }
 
 if (-not (Test-Path $NuGetExe)) {
-    # Using 5.3.0 to workaround https://github.com/NuGet/Home/issues/5016
     Write-Output "Downloading nuget.exe to $NuGetExe"
-    wget https://dist.nuget.org/win-x86-commandline/v5.3.0/nuget.exe -OutFile $NuGetExe
+    wget https://dist.nuget.org/win-x86-commandline/v5.6.0/nuget.exe -OutFile $NuGetExe
 }
 
 & $NuGetExe pack $NuspecFile `