Add ChangeLog file

Signed-off-by: Przemek Stekiel <przemyslaw.stekiel@mobica.com>
diff --git a/ChangeLog.d/mbedtls_ecp_export.txt b/ChangeLog.d/mbedtls_ecp_export.txt
new file mode 100644
index 0000000..50fa0b3
--- /dev/null
+++ b/ChangeLog.d/mbedtls_ecp_export.txt
@@ -0,0 +1,3 @@
+Features
+   * Add a function to export ECP keypair parameters.
+     Fixes #4838.