homeassistant: Restart after upgrade.

[ludeeus]

Description:

By changing it to this, Home Assistant can be upgraded while runnning.
This can be usefull for upgrading Home Assistant from Home Assistant, with shell_command, python_script, custom_component, and so on.

Acording to the documentation this is the default way to upgrade Home Assistant:
https://www.home-assistant.io/docs/installation/updating/

The default way to update Home Assistant to the latest release, when available, is:

$ pip3 install --upgrade homeassistant

After updating, you must restart Home Assistant for the changes to take effect. This means that you will have to restart hass

Checklist (Required):

• The code change is tested and works locally.
• The code is compliant with Contributing guidelines

If pertinent:

• Script has validation check of the job.
• Created/Updated documentation at /docs