Merge branch 'testing' into 'master'

Add some additions to README.

See merge request francois.techene/librem-manager!1
1 job for master in 46 seconds (queued for 2 seconds)
Name Stage Failure
failed
job Build
Get:5 http://repo.pureos.net/pureos byzantium/main Translation-en [5672 kB]
Fetched 12.8 MB in 5s (2740 kB/s)
Reading package lists...
$ apt-get -y install build-essential wget ca-certificates meson ninja
Reading package lists...
Building dependency tree...
E: Unable to locate package ninja
Cleaning up file based variables
ERROR: Job failed: exit code 1