Wrap file for jsoncpp

[koponomarenko]

Hey guys! I created a wrap file for jsoncpp lib, which already supports Meson. Following the instructions, I also created a repository: https://github.com/koponomarenko/jsoncpp . How can I transfer it to mesonbuild?

[koponomarenko]

• [x] project() has version string
• [x] project() has license string
• [x] if new project, master has tagged commit as only commit
• [x] if new branch, it is branched from master
• [x] contains a readme.txt
• [x] contains an upstream.wrap file
• [x] download link points to authoritative upstream location
• [ ] wrap repository contains only build system files
• [x] merge request is pointed to correct target branch (not master)
• [x] wrap works
• [x] repo does not have useless top level directory (i.e. libfoobar-1.0.0)

[sarum9in]

https://github.com/mesonbuild/jsoncpp is up, please create a PR targeting branch 1.8.4.