--no-binarycaching isn't documented

[brycelelbach]

@BillyONeal tells me that --no-binarycaching is an option, but alas it doesn't appear to be documented.

$ ~/development/nvidia/vcpkg/vcpkg --help | grep binary
  --binarysource=<path>           Add sources for binary caching. See 'vcpkg help binarycaching'
$ ~/development/nvidia/vcpkg/vcpkg install --help | grep binary
  --only-binarycaching            Fail if cached binaries are not available
  --editable                      Disable source re-extraction and binary caching for libraries on
                                  external binary caching.
                                  See `vcpkg help binarycaching` for more information.
  --binarysource=<path>           Add sources for binary caching. See 'vcpkg help binarycaching'