Update doc for 5.6

There are references to mbed OS 5.4 and CLI 1.0.0 (which are very old now).
@Patater please have a look to the markdown doc and update what you consider necessary for the 5.6 release (to be done in a branch).

Update: same applies to other uvisor examples.

Inspect the markdown documentation and the other uvisor examples for references to mbed OS 5.4 and CLI 1.0.0. Compare those references with the 5.6 release, update the outdated documentation in a branch, and confirm that the same updates are applied consistently across the examples.

Written by the indexing model from the issue text.