FindBoost: Add support for Boost 1.76
Update the list of known versions.
Run the command
cmake -DBOOST_DIR=/path/to/boost_1_76_0 \ -P Utilities/Scripts/BoostScanDeps.cmake
to extract dependencies from the 1.76.0 source tree. They are the same as 1.75's dependencies, so just update the version check for warning about newer versions.
Fixes: #22167 (closed)