Add buildroot utils/check-package check to the pr-checks.yml workflow.
It checks for common errors/mistakes when creating own buildroot
packages. Also fixed all warnings this utility output for our existing packages.
* Add 2020-10-28 beta EEPROM
This improves boot from USB and speeds up boot times.
also includes sd card v1 boot reliability.
see https://github.com/raspberrypi/rpi-eeprom/pull/246
Also add HDMI_DELAY=0 so HDMI display is always visible
for easier debugging.