Add ChangeLog entry
diff --git a/ChangeLog b/ChangeLog
index d5f28a8..8bebcc7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -19,6 +19,7 @@
    * Improve testing in configurations that omit certain hashes or
      public-key algorithms. Includes contributions by Gert van Dijk.
    * Improve negative testing of X.509 parsing.
+   * Improve the documentation of mbedtls_net_accept(). Contributed by Ivan Krylov.
 
 = mbed TLS 2.1.11 branch released 2018-03-16