Migrate lib and bin to NNBD

[friebetill]

You can already use the NNBD version with:

dev_dependencies:
  ...
  # Waiting for this PR https://bit.ly/31jtfUJ
  lang_table:
    git:
      url: https://github.com/KingWu/lang_table
      ref: 9f127d6
  ...