Document changes and release 5.12.0~rc6pureos1 of linux-next-librem5

Signed-off-by: Martin Kepplinger <martin.kepplinger@puri.sm>
2 jobs for next/byzantium in 74 minutes and 52 seconds (queued for 8 minutes and 2 seconds)
Status Job ID Name Coverage
  Build
passed #339575
librem5
build:aarch64

00:48:08

passed #339576
librem5:arm64
build:deb

01:07:11