Add ChangeLog entry

Add a ChangeLog entry for Jonathan Bennett's contribution which allows
loading symlinked certificates.
diff --git a/ChangeLog b/ChangeLog
index 1d39172..4a4d628 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
 mbed TLS ChangeLog (Sorted per branch, date)
 
+= mbed TLS X.X.X branch released XXXX-XX-XX
+
+Bugfix
+   * Allow loading symlinked certificates. Fixes #3005. Reported and fixed
+     by Jonathan Bennett <JBennett@incomsystems.biz> via #3008.
+
 = mbed TLS 2.20.0 branch released 2020-01-15
 
 Bugfix