faq: Update OVS/DPDK version table for OVS 2.11.
Indicate that OVS 2.11 uses DPDK 18.11.
@@ -176,6 +176,7 @@ Q: What DPDK version does each Open vSwitch release work with?
2.8.x 17.05.2
2.9.x 17.11.4
2.10.x 17.11.4
+ 2.11.x 18.11
============ =======
Q: Are all the DPDK releases that OVS versions work with maintained?
