Using openonu-go 1.2.7

Change-Id: Id7c9a57d29c7f1aeba99b833ffe0ae5b2c8c81c6
diff --git a/voltha-adapter-openonu/values.yaml b/voltha-adapter-openonu/values.yaml
index b60205e..972ffe0 100644
--- a/voltha-adapter-openonu/values.yaml
+++ b/voltha-adapter-openonu/values.yaml
@@ -120,5 +120,5 @@
   adapter_open_onu_go:
     registry: '{{ .Values.global.image_registry }}'
     repository: '{{ .Values.global.image_org }}voltha-openonu-adapter-go'
-    tag: '{{- if hasKey .Values.global "image_tag" }}{{- if .Values.global.image_tag }}{{ .Values.global.image_tag }}{{- else }}1.2.6{{- end }}{{- else }}1.2.6{{- end }}'
+    tag: '{{- if hasKey .Values.global "image_tag" }}{{- if .Values.global.image_tag }}{{ .Values.global.image_tag }}{{- else }}{{ .Chart.AppVersion }}{{- end }}{{- else }}{{ .Chart.AppVersion }}{{- end }}'
     pullPolicy: '{{ .Values.global.image_pullPolicy }}'