Support newly added Web APIs

[seratch]

The following endpoints are not yet supported.

• http://api.slack.com/methods/admin.users.session.invalidate
• https://api.slack.com/methods/apps.event.authorizations.list

Category (place an x in each of the [ ])

• slack.web.WebClient (Web API client)
• slack.webhook.WebhookClient (Incoming Webhook, response_url sender)
• slack.web.classes (UI component builders)
• slack.rtm.RTMClient (RTM client)

Requirements

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