Plaintext/clear passwords are not supported anymore but hashed passwords
still are. Mention that in the migration guide and point to the
appropriate location of documentation.
Cc: Quentin Schulz <foss+yocto@0leil.net>
(From yocto-docs rev: f8b9697ec7bcc188db5ce9e5067bc82c023b79d9)
Signed-off-by: Quentin Schulz <quentin.schulz@theobroma-systems.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>