Update supported releases to include 1.6.13 and 1.7.4 (#8410)
Update supported releases to include 1.6.13 and 1.7.4 (#8410)


istio/istio.io,istio/istio.io,istio/istio.io,istio/istio.io,istio/istio.io,istio/istio.io,istio/istio.io