Exclude test folder from Doxygen API reference

[JPenuchot]

Hi,

This should probably not be in the docs:

https://codedocs.xyz/jbeder/yaml-cpp/classVeryLoooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo72732a7a8cd04f0ab9551a6aaa86a0c2.html

You can exclude directories by setting the DOXYGEN_EXCLUDE_PATTERNS CMake variable, for example:

set(DOXYGEN_EXCLUDE_PATTERNS ${CMAKE_SOURCE_DIREC}/test/*)

Regards, Jules