Add JMESPath for C++ to the list of libraries

[robertmrk]

jmespath.cpp is a C++ implementation of JMESPath. The library is cross-platform, well tested and fully compliant with the specifications, it runs all the tests from jmespath.test. It's actually not a new library, I created it a few years ago but I forgot to request inclusion on the site.

It would be great if the library could be listed on the site.