roscpp is declared as a runtime dependency

Hi,

If I install this package from robotpkg's binaries:

╰─>$ grep Require /opt/openrobots/lib/pkgconfig/talos_data.pc
Requires: urdfdom >= 0.2.9, gazebo >= 7.0.0, roscpp

I think that roscpp is not really a required runtime dependency here, and I suggest to remove it.