Is your feature request related to a problem? Please describe.
The package cgal requires gmp, which on Windows requires yasm-tool:x86-windows, even when building using x64-windows. The vcpkg.json file does not have an option to set this.

Proposed solution
A triplet attribute, e.g.

{
  "name": "cdt-plusplus",
  "version": "0.1.8",
  "dependencies": [
    "catch2",
    "docopt",
    "date",
    "fmt",
    "ms-gsl",
    "eigen3",
    "pcg",
    "tbb",
    {
      "name": "yasm-tool",
      "platform": "windows",
      "triplet": "x86-windows"
    },
    "cgal"
  ]
}

Describe alternatives you've considered
I have to build in classic mode, but it gets confusing when you build in manifest mode on Travis-CI and GitHub actions, but then have to build in classic mode on AppVeyor. So far, this only works with a CMakeLists.txt such as:

https://github.com/acgetchell/CDT-plusplus/blob/develop/CMakeLists.txt

(All the lines before project()).

Additional context
https://ci.appveyor.com/project/acgetchell/cdt-plusplus#L557