device_state_attributes deprecated implementation

[amitkeret]

Describe the bug
During bootup, the following deprecated configuration generates this warning:

Entity sensor.chromecast_devices (<class 'custom_components.spotcast.sensor.ChromecastDevicesSensor'>) implements device_state_attributes. Please report it to the custom component author.
Entity sensor.playlists_sensor (<class 'custom_components.spotcast.sensor.ChromecastPlaylistSensor'>) implements device_state_attributes. Please report it to the custom component author.

• Using latest version of spotcast
• I have setup the Spotify integration in Home Assistant
• I am using multiple accounts
• Using latest stable version of Home Assistant
• I have Spotify Premium
• I'm attaching relevant logs with level debug for component spotcast (see README)
• I'm using entity_id in the service call and have tried device_name but the issue remains

Describe the bug

Environment (please complete the following information):

• HA version: 2021.12
• spotcast version: 3.6.21

[hmmbob]

Fix already in #271, waiting to get merged and released