infra: Rework labeler.yml file.
infra: Rework labeler.yml file.

Convert to the other style of YAML lists which matches the documentation
at https://github.com/actions/labeler#basic-examples and
https://github.com/actions/labeler#common-examples

Signed-off-by: Tim 'mithro' Ansell <b1c1d8736f20db3fb6c1c66bb1455ed43909f0d8@mith.ro>

google/skywater-pdk