Update iPhone app version (home-assistant#7933)

The Dec 22, 2018 app update is still compatible with the procedure.

source/_components/vacuum.xiaomi_miio.markdown

@@ -136,7 +136,7 @@ The following table shows the units of measurement for each attribute:
 <p class='note'>
 As per [python-miio issue 185](https://github.com/rytilahti/python-miio/issues/185) the Android Mi Home app no longer stores the token within the database (it's retrieved from Xiaomi servers from version 5.0.31+). Currently the only known fix is to uninstall, then install a downgraded version of the apk. Apkmirror is a trusted source for older versions of the app. [Mi-Home version 5.0.30](https://www.apkmirror.com/apk/xiaomi-inc/mihome/mihome-5-0-30-release/) is confirmed as working for the following Android methods. Using older version than 5.0.30 is not recommended as it might lack support for some newer devices like the Roborock S50.
 <br/> <br/>
-The iPhone app still stores the token in the sqlite db as of v4.9.1 (Nov 7, 2018).
+The iPhone app still stores the token in the sqlite db as of v4.10.2 (Dec 22, 2018).
 <br/> <br/>
 This token (32 hexadecimal characters) is required for the Xiaomi Mi Robot Vacuum, Mi Robot 2 (Roborock) Vacuum, Xiaomi Philips Lights and Xiaomi IR Remote. The Xiaomi Gateway uses another security method and requires a `key` (16 alphanumeric chars), which can be obtained
 easily via a hidden menu item at the Mi-Home app or using the `miio` command line tool.