release-20220511

Other changes:

• Build a container image with the SDK that can be used for building, e.g.:

  docker pull ghcr.io/clj/esp8266-nim-sdk:latest
  

  then

  docker run  -it  --rm  -v (pwd):/src -w="/src" esp8266-nim-sdk make
  

  or

  docker run  -it  --rm  -v (pwd):/src -w="/src" esp8266-nim-sdk
  

  to get an interactive shell.