Add accessor function from mbedtls_ssl_context to the configuration

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/ChangeLog.d/ssl_context-user_data.txt b/ChangeLog.d/ssl_context-user_data.txt
index 81df94a..1198847 100644
--- a/ChangeLog.d/ssl_context-user_data.txt
+++ b/ChangeLog.d/ssl_context-user_data.txt
@@ -1,3 +1,5 @@
 Features
    * The structures mbedtls_ssl_config and mbedtls_ssl_context have an
      extra field user_data which is reserved for the application.
+   * Add an accessor function to get the configuration associated with
+     an SSL context.