Slack - Join Conversation

Joins an existing conversation in Slack. This atomic requires the following API scope: channels:join.

Target: Slack integration target or an HTTP Endpoint for "slack.com" with a path of "/api"

Account Key: None if using an integration-provided target, access token if using an HTTP Endpoint target

Steps:
[] Build the authorization header and the request payload
[] Request to join the conversation
[] Check if the request was successful:
[]> If it wasn't, return an error
[] Extract the request status
[] Check if the request status was successful:
[]> If it wasn't, return an error

More information about this API: https://api.slack.com/methods/conversations.join