Release v2.2.0 preparation

[ed-xmos]

https://xmosjira.atlassian.net/browse/AP-196

• [ ] Remove bad link workaround when fwk_rtos updated
• [x] Update to released version fwk_voice 0.7.0

[ed-xmos]

Everything looks okay. I have raised one concern, but it is not backed up by any evidence.

This is not the final merge - there are a couple more to develop, then release staging. I have asked Tom about what sort of final review we need.