I had the same problem and made the following changes and it builds successfully now:
external_components:
- source:
type: git
url: https://github.com/screekworkshop/custom_components_support_for_screek_2a
ref: main
components: [uart]
And added the following to the PIN configuration:
output:
- platform: gpio
id: board_info_ed
pin:
number: GPIO12
ignore_pin_validation_error: true