AETHER-487 Add support of k8s 1.18

Change-Id: I759b71546e6ba2fc1a52ab135ea26c403fecc417
diff --git a/omec/omec-user-plane/templates/networks.yaml b/omec/omec-user-plane/templates/networks.yaml
index b749ea8..37f54e7 100644
--- a/omec/omec-user-plane/templates/networks.yaml
+++ b/omec/omec-user-plane/templates/networks.yaml
@@ -15,6 +15,9 @@
 {{- end }}
 spec:
   config: '{
+{{- if semverCompare ">=1.16-0" .Capabilities.KubeVersion.GitVersion }}
+    "cniVersion": "0.3.1",
+{{- end }}
     "type": {{ .Values.config.upf.cniPlugin | quote }},
     "ipam": {
         "type": {{ .Values.config.upf.ipam | quote }}
@@ -31,6 +34,9 @@
 {{- end }}
 spec:
   config: '{
+{{- if semverCompare ">=1.16-0" .Capabilities.KubeVersion.GitVersion }}
+    "cniVersion": "0.3.1",
+{{- end }}
     "type": {{ .Values.config.upf.cniPlugin | quote }},
     "ipam": {
         "type": {{ .Values.config.upf.ipam | quote }}