docs: Updated faq with details on how to keep on top of updates

_docs/faq.md

@@ -12,6 +12,7 @@
   - [I'm an agile user and having trouble setting up a target rate sensor. What am I doing wrong?](#im-an-agile-user-and-having-trouble-setting-up-a-target-rate-sensor-what-am-i-doing-wrong)
   - [My gas consumption/costs seem out](#my-gas-consumptioncosts-seem-out)
   - [I want to use the tariff overrides, but how do I find an available tariff?](#i-want-to-use-the-tariff-overrides-but-how-do-i-find-an-available-tariff)
+  - [How do I know when there's any update available?](#how-do-i-know-when-theres-any-update-available)
   - [I've been asked for my meter information in a bug request, how do I obtain this?](#ive-been-asked-for-my-meter-information-in-a-bug-request-how-do-i-obtain-this)
   - [How do I increase the logs for the integration?](#how-do-i-increase-the-logs-for-the-integration)
 
@@ -101,6 +102,12 @@ In this scenario, the `code` is `VAR-22-11-01` and so the product url is [https:
 
 ![Target product example](./assets/product_tariff_lookup.png)
 
+## How do I know when there's any update available?
+
+If you've installed via HACS, then you can keep an eye on `sensor.hacs` to see the number of pending updates. This could be used with an automation or highlighted on your dashboard. This will include any HACS integration update, not just this one. If you're feeling a little more adventurous, then you can enable HACS' [experimental features](https://hacs.xyz/docs/configuration/options/). This will surface any available updates in the normal update location within Home Assistant.
+
+If you've installed the integration manually, then you should keep an eye on the [GitHub releases](https://github.com/BottlecapDave/HomeAssistant-OctopusEnergy/releases). You could even subscribe to the [RSS feed](https://github.com/BottlecapDave/HomeAssistant-OctopusEnergy/releases.atom).
+
 ## I've been asked for my meter information in a bug request, how do I obtain this?
 
 If you've been asked for meter information, don't worry we won't ask for anything sensitive. To obtain this information