Use renamed jetstream env variable

Signed-off-by: Han Verstraete (OpenFaaS Ltd) <[email protected]>

Author: welteki

chart/openfaas/templates/gateway-dep.yaml

@@ -138,7 +138,7 @@ spec:
         {{- end }}
         {{- end }}
         {{- if eq .Values.queueMode "jetstream" }}
-        - name: faas_nats_jetstream
+        - name: nats_jetstream
           value: "true"
         {{- end }}
         {{- if .Values.basic_auth }}