📚 Adds add-on deprecation warnings to README's

homebridge/.README.j2

@@ -9,6 +9,24 @@
 This add-on provides the installation, configuration, and integration for
 [Homebridge][homebridge].
 
+## Deprecation warning
+
+**This add-on is in a deprecated state!**
+
+At this point it is unsure how long this add-on keeps available or
+updated.
+
+This add-on was originally developed to add HomeKit support to
+Home Assistant. Meanwhile, Home Assistant gained native support
+for HomeKit.
+
+<https://www.home-assistant.io/components/homekit/>
+
+Because of this, is very likely that the plugins this add-on rely, on
+will no longer be developed or maintained.
+
+We **STRONGLY** suggest to migrate to the Home Assistant HomeKit component.
+
 ## About
 
 Homebridge is a server that emulates the iOS HomeKit API, allowing you to
@@ -65,7 +83,7 @@ If you are more interested in stable releases of our add-ons:
 <https://github.com/hassio-addons/repository>
 
 {% endif %}
-[project-stage-shield]: https://img.shields.io/badge/project%20stage-production%20ready-brightgreen.svg
+[project-stage-shield]: https://img.shields.io/badge/project%20stage-%20!%20DEPRECATED%20%20%20!-ff0000.svg
 [forum-shield]: https://img.shields.io/badge/community-forum-brightgreen.svg
 [forum]: https://community.home-assistant.io/t/community-hass-io-add-on-homebridge/33803?u=frenck
 [discord-shield]: https://img.shields.io/discord/330944238910963714.svg
@@ -76,4 +94,4 @@ If you are more interested in stable releases of our add-ons:
 [docs]: {{ repo }}/blob/{{ version }}/README.md
 [buymeacoffee-shield]: https://www.buymeacoffee.com/assets/img/guidelines/download-assets-sm-2.svg
 [buymeacoffee]: https://www.buymeacoffee.com/frenck
-[homebridge]: https://github.com/nfarina/homebridge
+[homebridge]: https://github.com/nfarina/homebridge