Bump to xamarin/NRefactory/master@f3242923

[jonpryor]

Changes: xamarin/NRefactory@495405a...f324292

• xamarin/NRefactory@f3242923: Add .NET 6.0 target framework
• xamarin/NRefactory@074fabe9: Merge pull request "clang" is not always available. It needs to be customizible. #3 from xamarin/net6
• xamarin/NRefactory@fb5f1535: Merge pull request Fix Xamarin.Android.sln build with xbuild #4 from xamarin/dev/sandy/obsolete
• xamarin/NRefactory@9233d6a8: Merge pull request [Xamarin.Android.Build.Tasks] Import from monodroid/301e7238 #5 from xamarin/dev/sandy/mergemain
• xamarin/NRefactory@b2991f92: Merge remote-tracking branch 'origin/master' into dev/sandy/mergemain
• xamarin/NRefactory@e9c0609e: Fix use of obsolete member
• xamarin/NRefactory@a6885a74: Allow building with .NET 6

[jonpryor]

PR doesn't build, because NRefactory uses MD5:

       (CoreCompile target) -> 
         /Users/builder/azdo/_work/1/s/xamarin-android/external/nrefactory/ICSharpCode.NRefactory.CSharp/Parser/mcs/MonoSymbolTable.cs(723,23): error CA5351: WriteData uses a broken cryptographic algorithm MD5 [/Users/builder/azdo/_work/1/s/xamarin-android/external/nrefactory/ICSharpCode.NRefactory.CSharp/ICSharpCode.NRefactory.CSharp.csproj]
         /Users/builder/azdo/_work/1/s/xamarin-android/external/nrefactory/ICSharpCode.NRefactory.CSharp/Parser/mcs/MonoSymbolTable.cs(782,16): error CA5351: CheckChecksum uses a broken cryptographic algorithm MD5 [/Users/builder/azdo/_work/1/s/xamarin-android/external/nrefactory/ICSharpCode.NRefactory.CSharp/ICSharpCode.NRefactory.CSharp.csproj]
         /Users/builder/azdo/_work/1/s/xamarin-android/external/nrefactory/ICSharpCode.NRefactory.CSharp/Parser/mcs/context.cs(783,25): error CA5351: GetChecksumAlgorithm uses a broken cryptographic algorithm MD5 [/Users/builder/azdo/_work/1/s/xamarin-android/external/nrefactory/ICSharpCode.NRefactory.CSharp/ICSharpCode.NRefactory.CSharp.csproj]
         /Users/builder/azdo/_work/1/s/xamarin-android/external/nrefactory/ICSharpCode.NRefactory.CSharp/Parser/mcs/assembly.cs(542,23): error CA5350: GetPublicKeyToken uses a weak cryptographic algorithm SHA1 [/Users/builder/azdo/_work/1/s/xamarin-android/external/nrefactory/ICSharpCode.NRefactory.CSharp/ICSharpCode.NRefactory.CSharp.csproj]

However, use of MD5 is not new; our current commit uses it! I therefore have to assume that "something else" is causing CA5351 to be applicable. I wonder if if the migration to use /Project/@Sdk projects in xamarin/NRefactory@a6885a7 is the cause? I am uncertain.

In the meantime, we can't merge this, and xamarin/NRefactory doesn't allow filing issues, so…. Leave this PR open as a draft for eternity?