Passing a .resx file ({0}) as a source file to the compiler is deprecated. Use resgen.exe to transform the .resx file into ...

Passing a .resx file ({0}) as a source file to the compiler is deprecated. Use resgen.exe to transform the .resx file into a .resources file to pass as a --resource option. If you are using MSBuild, this can be done via an  item in the .fsproj project file.