faq: Update OVS/DPDK version table for OVS 2.12.
Indicate that OVS 2.12 uses DPDK 18.11.2.
@@ -179,6 +179,7 @@ Q: What DPDK version does each Open vSwitch release work with?
2.9.x 17.11.4
2.10.x 17.11.4
2.11.x 18.11.2
+ 2.12.x 18.11.2
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Q: Are all the DPDK releases that OVS versions work with maintained?
