iCub Software release 1.21.0

What's Changed

• AMO diagnostics by @marcoaccame in #751
• iCub::iKin::iCubEye 2.8 by @pattacini in #752
• AMO data to YARP ports by @marcoaccame in #753
• Remove references to deprecated YARP interfaces by @traversaro in #755
• use YCM 0.13.0 by @pattacini in #756
• Update script for generating the deb packets for using ycm 0.13.0 by @Nicogene in #757
• Only raise a fatal error on icub_firmware_shared version if icub_firmware_shared is used by @traversaro in #760
• CanBusMotionControl: corrected compilation warnings + potential bugs by @marcoaccame in #761

Full Changelog: v1.20.0...v1.21.0