[boost] 1.68 Getting Started links to 1.67

Hi,

The most reliable way to get a copy of Boost is to download boost_1_67_0.7z or boost_1_67_0.zip and unpack it to install a complete Boost distribution.1

1.67? Actually the best way is to use vcpkg if possible (IMO). https://www.boost.org/doc/libs/1_68_0/more/getting_started/windows.html -- Olaf