Add ChangeLog entry
Add a ChangeLog entry for Jonathan Bennett's contribution which allows
loading symlinked certificates.
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
