Merge with Klipper

[kpishere]

Can you tell me exactly what commit number your took your effective branch from to make this repo? I could get a PR prepared for you on this.

[kpishere]

Think I happened to find it by a good guess of the dates and the fact that there was not much activity over the summer. Looks like you took it from ...

commit 121052ad396ff54ea76b3ea2c05fba4acd2a158b (HEAD -> update-python3)
Author: Justin Schuh jschuh@users.noreply.github.com
Date: Fri Jul 9 06:55:16 2021 -0700

spi_flash: Support firmware dictionary validation

Updates firmware validation to use a dictionary if provided (or found
when updating from the default out/ directory).

Validation without a dictionary still checks the following (in order):
1. Active firmware's raw dictionary changed after update
2. Checksum of firmware.cur matches expected

Signed-off-by: Justin Schuh <code@justinschuh.com>