Update README.md

Author: mikker

README.md

@@ -1,3 +1,7 @@
+**NOTE:** Passwordless is currently going through some breaking changes. Be aware that the docs in `master` aren't necessarily the same as for you installed version.
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 <p align='center'>
   <img src='https://s3.brnbw.com/Passwordless-title-gaIVkX0sPg.svg' alt='Passwordless' />
   <br />