Rename "password" to "token" in gong.json

I just setup with someone and wi noticed that gong.json needs a Jira token where it says password.

Also, it would be helpful to add an example to the README:

    "client":"jira",
    "domain":"<JIRA_DOMAIN>,
    "password":"<JIRA_API_TOKEN>",
    "project_prefix":"<PROJECT_PREFIX>",
    "transitions":"In Progress",
    "username":"<JIRA_EMAIL>"
}