Update README

Author: mkuratczyk

README.md

@@ -9,7 +9,9 @@
 [![Build Status](https://github.com/erlang/docker-erlang-otp/workflows/erlang/badge.svg)](https://github.com/erlang/docker-erlang-otp/actions)
 
 This is used as docker base image for Erlang OTP.
-The goal is to provide images for a few last erlang releases (currently 25 / 24 / 23 / 22 / 21 / 20 / 19 / 18), in close to full feature Erlang OTP, and relatively slim images. Support to 17, R16 and R15 are provided in this repo on a best-effort basis, and not part of official-image effort in docker-library/official-images#1075 .
+The goal is to provide up-to-date images for supported Erlang releases in close to full feature Erlang OTP, and relatively slim images.
+Images for unsupported Erlang releases are provided on a best-effort basis (generally speaking, old images may still be used,
+but no new images are built for such releases).
 
 ### use the Erlang 23