Add pthreads to vcpkg packages list in User Manual
Add pthreads to vcpkg packages list in User Manual

jan-cerny/openscap,OpenSCAP/openscap,mpreisler/openscap,OpenSCAP/openscap,OpenSCAP/openscap,jan-cerny/openscap,redhatrises/openscap,redhatrises/openscap,jan-cerny/openscap,jan-cerny/openscap,OpenSCAP/openscap,mpreisler/openscap,OpenSCAP/openscap,OpenSCAP/openscap,mpreisler/openscap,jan-cerny/openscap,jan-cerny/openscap,redhatrises/openscap,mpreisler/openscap,redhatrises/openscap,mpreisler/openscap,redhatrises/openscap,redhatrises/openscap,mpreisler/openscap