sensors.yaml:
- platform: rest
  name: Home Assistant Released Version
  json_attributes:
      - body
      - html_url
  resource: https://api.github.com/repos/home-assistant/home-assistant/releases/latest
  username: !secret github_username
  password: !secret github_access_token
  authentication: basic
  value_template: '{{ value_json.tag_name }}'
  headers:
    Accept: application/vnd.github.v3+json
    Content-Type: application/json
    User-Agent: Home Assistant REST sensor
- platform: version

automation.yaml:

- alias: Home Assistant Release Check
  initial_state: on
  trigger:
  - platform: state
    entity_id: sensor.home_assistant_release
  - platform: homeassistant
    event: start
  condition:
    condition: template
    value_template:  "{{ states('sensor.home_assistant_released_version') != states('sensor.current_version') }}"
  action:
  - service: persistent_notification.create
    data_template:
      title: Home Assistant Release
      message: >-
        A new version of Home Assistant is available, {{ states('sensor.home_assistant_released_version') }}, while current version is {{states('sensor.current_version') }}

        Link: {{states.sensor.home_assistant_released_version.attributes.html_url}}

        Release notes:

        {{states.sensor.home_assistant_released_version.attributes.body.split("## All changes")[0]}}

  - service: notify.telegram_notifier
    data_template:
      message: >-
        A new version of Home Assistant is available, {{ states('sensor.home_assistant_released_version') }}, while current version is {{states('sensor.current_version') }}

        Link: {{states.sensor.home_assistant_released_version.attributes.html_url}}

        Release notes:

        {{states.sensor.home_assistant_released_version.attributes.body.split("## All changes")[0]}}