Device class attribute is missing in MQTT discovery payload

[definitio]

Operating environment/Installation (Hass.io/Docker/pip/etc.):

Arch Linux, Python 3.9, pip.

ESP (ESP32/ESP8266, Board/Sonoff):

ESP32

ESPHome version (latest production, beta, dev branch)

1.17.0

Affected component:

https://esphome.io/components/sensor/index.html

Description of problem:
Setting device_class doesn't work.

Problem-relevant YAML-configuration entries:

sensor:
  - platform: template
    name: $room illuminance
    state_topic: ${room}/sensor/illuminance
    device_class: illuminance
    lambda: 'return id(indoor_illuminance_raw).state;'
    update_interval: 10s
    filters:
      - sliding_window_moving_average:
          window_size: 6
          send_every: 6
          send_first_at: 6

Additional information and things you've tried:
Icon is also missing. It was there in the previous version.

[probot-esphome]

mqtt source
mqtt issues
mqtt recent changes
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[OttoWinter]

Yeah the mqtt integration just hasn't added that feature yet. PRs to add this to MQTTSensorComponent are welcome!

[definitio]

Fixed

[krconv]

The fix for sensors is working great 🥳 ; just posted a fix for covers in esphome/esphome#2092