Updated README (parse-community#4325)

Added a link to the new SendinBlue adapter for parse-server

Author: Kira2

README.md

@@ -311,6 +311,7 @@ You can also use other email adapters contributed by the community such as:
 - [parse-server-mandrill-adapter](https://www.npmjs.com/package/parse-server-mandrill-adapter)
 - [parse-server-simple-ses-adapter](https://www.npmjs.com/package/parse-server-simple-ses-adapter)
 - [parse-server-mailgun-adapter-template](https://www.npmjs.com/package/parse-server-mailgun-adapter-template)
+- [parse-server-sendinblue-adapter](https://www.npmjs.com/package/parse-server-sendinblue-adapter)
 - [parse-server-mailjet-adapter](https://www.npmjs.com/package/parse-server-mailjet-adapter)
 - [simple-parse-smtp-adapter](https://www.npmjs.com/package/simple-parse-smtp-adapter)