update nuspec

[huaxing-yuan]

This pull request makes several updates to the .nuspec files for AxaFrance.WebEngine.ReportViewer and AxaFrance.WebEngine.Runner. The changes include updating dependency versions, removing support for .NET 6.0, and cleaning up related file references.

Dependency Updates:

• Updated AvalonEdit to version 6.3.1.120 in the AxaFrance.WebEngine.ReportViewer package.
• Updated Microsoft.Web.WebView2 to version 1.0.3351.48 and SkiaSharp to version 3.119.0 in the AxaFrance.WebEngine.ReportViewer package.
• Updated SkiaSharp to version 3.119.0 and System.Text.Json to version 9.0.7 in the AxaFrance.WebEngine.Runner package.

Removal of .NET 6.0 Support:

• Removed dependency groups for .NET 6.0 in both AxaFrance.WebEngine.ReportViewer and AxaFrance.WebEngine.Runner. [1] [2]
• Removed file references for .NET 6.0 in the contentFiles and lib sections of both .nuspec files. [1] [2] [3] [4]

Repository Metadata:

• Removed the commit attribute from the repository metadata in the AxaFrance.WebEngine.Runner package.