add Canny Pigeons

README.md

@@ -875,6 +875,7 @@ This list results from Pull Requests, reviews, ideas, and work done by 1600+ peo
   * [Bump](https://bump.email/) - Free 10 Bump email addresses, one custom domain
   * [Burnermail](https://burnermail.io/) - Free 5 Burner Email Addresses, 1 Mailbox, 7-day Mailbox History
   * [Buttondown](https://buttondown.email/) - Newsletter service. Up to 100 subscribers free
+  * [Canny Pigeons](https://cannypigeons.com/) - DMARC monitoring platform with DNS drift alerts, IP threat intel and unlimited users. First domain is free - no credit card required.
   * [Conduit](https://conduit.email/) - Turn incoming emails into webhooks to trigger your API from emails. The service is completely free.
   * [Contact.do](https://contact.do/) - Contact form in a link (bitly for contact forms)
   * [debugmail.io](https://debugmail.io/) - Easy to use testing mail server for developers