autobump: remove docfx (as it needs dotnet@8)

[chenrui333]

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docfx needs dotnet@8 (but it is still in preview status at the moment, https://github.com/dotnet/installer/releases/tag/v8.0.100-preview.3.23178.7), removing it and we can bring it back once we have dotnet@8

  /opt/homebrew/Cellar/dotnet/7.0.100/libexec/sdk/7.0.100/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.TargetFrameworkInference.targets(144,5): error NETSDK1045: The current .NET SDK does not support targeting .NET 8.0.  Either target .NET 7.0 or lower, or use a version of the .NET SDK that supports .NET 8.0. [/private/tmp/docfx-20230411-38464-py7up6/docfx-2.65.2/src/docfx/docfx.csproj::TargetFramework=net8.0]

relates to:

• docfx 2.63.1 #126764
• docfx 2.64.0 #127263
• docfx 2.65.0 #127779
• docfx 2.65.2 #128138