Default triplets to the correct macOS deployment target

i.e. use `arm64-osx-min1100-release` instead of `arm64-osx-release` and `x64-osx-min1015-release` instead of `x64-osx-release` etc. by default in `scripts/install-vcpkg-deps`. Both our and upstream's CI already uses these by explicitly specifying the corresponding triplets, but it would be nice to do this for local developers too to fix the corresponding linker warnings when building Mixxx.