CMake error when linking with Clang-cl (lld-link); requires vcpkg update

[Farwaykorse]

When building with CMake and Clang-cl.
CMake reports an error while linking. See: AppVeyor build of MS/GSL

 The C++ compiler "C:\Program Files\LLVM\bin\clang-cl.exe" is not able to
  compile a simple test program.
...
lld-link.exe : error : could not open C:\Tools\vcpkg\installed\x86-windows\debug\lib\*.lib: no such file or directory

This is a known issue with the installed vcpkg version.
Issue: microsoft/vcpkg#4359
Fixed in: microsoft/vcpkg#4573

Temporary workaround:
Pull the latest vcpkg sources during the install phase. See: documentation. (Bootstrapping vcpkg is not needed.)

install:
  - cd C:\Tools\vcpkg
  - git pull
  - cd %APPVEYOR_BUILD_FOLDER%

[IlyaFinkelshteyn]

@Farwaykorse thank you for the report. As part of #2733 we will update vspkg during next build worker image update.

[XVilka]

Isn't this one fixed already?

[IlyaFinkelshteyn]

Yes, it must be, closing, Thanks @XVilka