Added release note for 1.3.3

doc/release_notes/ProxySQL_v1.3.3.md

@@ -0,0 +1,17 @@
+## ProxySQL v1.3.3
+
+Release date: 2016-12-29
+
+Stable release v1.3.3 , released on 2017-01-20
+
+Compared to v1.3.2, has the following bugs fixed / enhancements:
+
+* MySQL Protocol: handle for mysql [bug 66884](https://bugs.mysql.com/bug.php?id=66884) that could cause infinite loop [#873](../../../../issues/873)
+* MySQL Protocol: improved SSL connection over slow network, workaround for bug CONC-225 [#883](../../../../issues/833)
+* Query routing: in some circumstances `transaction_persistent` could disable routing after commit #889](../../../../issues/889)
+* Admin: `Latency_us` was incorrectly named `Latency_ms` [#882](../../../../issues/882)
+* Admin: improved scalability on access to `mysql_servers`
+* General: improved sypport for systemd
+* General: init script returns codes for LSB compliance
+* MySQL Protocol: removed assert() for unknown commands, and replaced with an error [#859](../../../../issues/859)
+* MySQL Protocol: return an error for `COM_PROCESS_KILL`, deprecated command [#858](../../../../issues/858)