The 'env' trait of a KernelSpec instance expected a dict, not the list

[jzhuge]

Error when opening the kernel:

traitlets.traitlets.TraitError: The 'env' trait of a KernelSpec instance expected a dict, not the list [['COURSIER_REPOSITORIES', '...

It has been broken since 0.14.0-RC.15. Run this script to reproduce:

almond_version=${1:-0.14.1}
scala212="2.12.20"
s3support_version="0.2.0"
coursier_repo="repo-dummy"

cs launch   --use-bootstrap sh.almond:launcher_3:${almond_version} -- \
            --scala ${scala212} \
            --install \
            --jupyter-path /usr/local/share/jupyter/kernels \
            --display-name "Scala (Almond ${almond_version})" \
            --id scala-${almond_version} \
            --env "COURSIER_REPOSITORIES=${coursier_repo}"

Kernel.json for different releases:

tail /usr/local/share/jupyter/kernels/scala-*/kernel.json
==> /usr/local/share/jupyter/kernels/scala-0.14.0-RC14/kernel.json <==
    "COURSIER_REPOSITORIES=repo-dummy",
    "--connection-file",
    "{connection_file}"
  ],
  "display_name": "Scala (Almond 0.14.0-RC14)",
  "language": "scala",
  "env": {
    "COURSIER_REPOSITORIES": "repo-dummy"
  }
}
==> /usr/local/share/jupyter/kernels/scala-0.14.0-RC15/kernel.json <==
  ],
  "display_name": "Scala (Almond 0.14.0-RC15)",
  "language": "scala",
  "env": [
    [
      "COURSIER_REPOSITORIES",
      "repo-dummy"
    ]
  ]
}
==> /usr/local/share/jupyter/kernels/scala-0.14.1/kernel.json <==
  ],
  "display_name": "Scala (Almond 0.14.1)",
  "language": "scala",
  "env": [
    [
      "COURSIER_REPOSITORIES",
      "repo-dummy"
    ]
  ]
}