feat: Add PlaybackGrant

[sarahcstringer]

Fixes

Add PlaybackGrant.

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[sarahcstringer]

@shwetha-manvinkurke For this one, I was able to validate that using the PlaybackGrant generated a token I could use to connect

playback_grant = Twilio::JWT::AccessToken::PlaybackGrant.new
playback_grant = {'requestCredentials' =>  nil, 'playbackUrl' =>  'https://...', 'playerStreamerSid' =>  'VJXXX'}

token = Twilio::JWT::AccessToken.new(
  account_sid, api_key, api_secret,
  [playback_grant]
)

# Generate the token
puts token.to_jwt

[shwetha-manvinkurke]

Shouldn't be too hard to break this up though. Instead of :grant, you would do something like:

attr_accessor :requestCredentials,
              :playbackUrl,
              :playbackStreamerSid

[shwetha-manvinkurke]

payload = {}
payload[:requestCredentials] = requestCredentials if requestCredentials
payload[:playbackUrl] = playbackUrl if playbackUrl
payload[:playbackStreamerSid] = playbackStreamerSid if playbackStreamerSid

[shwetha-manvinkurke]

playback_grant.playbackStreamerSid = "VJXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"
playback_grant.playbackUrl = "https://000.us-east-1.playback.live-video.net/api/video/v1/us-east-000.channel.000?token=xxxxx"
@scat.add_grant(playback_grant)