Merge pull request #620 from humanmade/backport-619-to-v20-branch

[Backport v20-branch] Document file integrity recommendation

Author: mikelittle

other-docs/guides/updating-wordpress.md

@@ -0,0 +1,18 @@
+# Updating WordPress
+
+We recommend that you automate updates to your Altis project using the techniques described
+in [Automating Updates](./automatic-updates.md).
+
+However, if you want to update to the latest WordPress security release without updating all other Altis modules, you can do so by
+running the following command:
+
+```bash
+composer update altis/cms --with-dependencies
+```
+
+This will update the `altis/cms` module to the latest version and update any dependencies that are required for that
+version including WordPress itself.
+
+Note this will only update bug fix and security releases of WordPress. If there is a new major version of WordPress, that will be
+included in a later version of Altis. If you want to update to a new major version you will need to [update to the latest version of
+Altis](docs://guides/upgrading/).