Updated BREAKING CHANGES with psr/log v3 support

Author: ezimuel

BREAKING_CHANGES.md

@@ -1,3 +1,8 @@
+# 7.17
+
+- We changed the signature of `Elasticsearch\Common\EmptyLogger::log` adding the `void` return type.
+  This change has been needed to support psr/log v3.
+
 # 7.4
 
 - Using a deprecated parameter is notified triggering a [E_USER_DEPRECATED](https://www.php.net/manual/en/errorfunc.constants.php)