Updated FAQ

FAQ.md

@@ -54,6 +54,7 @@ For authorizing:
 * Apple iCloud, see [question 148](#user-content-faq148) ([German](https://support.apple.com/de-de/HT204397))
 * Free.fr, see [question 157](#user-content-faq157)
 * Posteo: please check if [additional email account protection](https://posteo.de/en/help/activating-additional-email-account-protection) ([German](https://posteo.de/hilfe/zusaetzlichen-postfachschutz-deaktivieren)) isn't enabled
+* Posteo: not that there is [no spam folder](https://posteo.de/en/help/how-does-the-posteo-spam-filter-work) ([German](https://posteo.de/hilfe/wie-funktioniert-der-posteo-spamfilter))
 * Web.de: please check if [IMAP is enabled](https://hilfe.web.de/pop-imap/imap/imap-serverdaten.html)
 * Web.de: with two factor authentication you'll need to use [an app password](https://web.de/email/sicherheit/zwei-faktor-authentifizierung/)
 * GMX: please check if [IMAP is enabled](https://support.gmx.com/pop-imap/toggle.html) ([German](https://hilfe.gmx.net/pop-imap/einschalten.html)). Reportedly, you need to do this on a desktop computer.