Add GitHub label workflow configuration

[ecalifornica]

In response to issue #7, this change adds configuration for the current set of default Github labels, as well as the Github Action workflow configuration to update the labels.

This requires an update to the repository Actions permissions, adding Workflow write permissions for the GITHUB_TOKEN generated per workflow run. Without this permission the workflow will fail to update the labels.

You can modify the permissions for the GITHUB_TOKEN in individual workflow files. If the default permissions for the GITHUB_TOKEN are restrictive, you may have to elevate the permissions to allow some actions and commands to run successfully.

• https://docs.github.com/en/actions/security-guides/automatic-token-authentication#modifying-the-permissions-for-the-github_token

Link to permissions setting, to be changed by a repository admin: https://github.com/biocommons/biocommons.example/settings/actions

Screenshot of permissions change: