Update dotnet-outdated

Update the default dotnet-outdated version to 4.6.0.

Author: martincostello

.github/workflows/update-dotnet-sdk.yml

@@ -71,7 +71,7 @@ on:
         description: 'The version of the dotnet-outdated .NET global tool to use if update-nuget-packages is true.'
         required: false
         type: string
-        default: '4.5.3'
+        default: '4.6.0'
       include-nuget-packages:
         description: 'A comma-separated list of NuGet package IDs (or substrings) to update, if update-nuget-packages is true.'
         required: false