Fixes ezvcpkg silently skipping outdated ports

[GhisBntly]

vcpkg install does not upgrade already installed ports, it silently skips them.

Normally, the command to run is vcpkg upgrade --no-dry-run, but for some reason it removes the port's folder in the packages/ directory, and cesium-native's CMakeLists.txt rely on it to install headers and libs!

So in this PR I am suggesting vcpkg remove --outdated --recurse instead, which does the job.

Note that relying on the content of the packages/ folder is not such a good idea, because when cleaning the (ez)vcpkg folder and letting vcpkg re-install using "binarysource" (archives cache), only the installed/ folder is populated, not the packages/, thus breaking the cesium-native build. The header and library file list to install should rather be extracted from the installed/vcpkg/info/<port>_<version>_<triplet>.list files instead.