Update helm chart kubeVersion to '>= 1.17.0' (#110)

helm chart kubernetes version did not match the minimal version
as supported by the network-operator.

change helm chart to the correct version.

Signed-off-by: Mamduh Alassi <mamduhala@nvidia.com>

deployment/network-operator/Chart.yaml

@@ -1,7 +1,7 @@
 apiVersion: v2
 name: network-operator
 version: 0.2.0-beta
-kubeVersion: '>= 1.15.0'
+kubeVersion: '>= 1.17.0'
 appVersion: v0.2.0
 description: Nvidia Mellanox network operator
 type: application