Update the voltha stack chart for latest openonu adapter chart version

Change-Id: I42389c433d4a2d2fad75fdc7e19109546f3be1e2
diff --git a/voltha-adapter-openonu/values.yaml b/voltha-adapter-openonu/values.yaml
index cd7ec06..f4d0f50 100644
--- a/voltha-adapter-openonu/values.yaml
+++ b/voltha-adapter-openonu/values.yaml
@@ -122,5 +122,5 @@
   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 }}1.2.4{{- end }}{{- else }}1.2.4{{- end }}'
+    tag: '{{- if hasKey .Values.global "image_tag" }}{{- if .Values.global.image_tag }}{{ .Values.global.image_tag }}{{- else }}1.2.5{{- end }}{{- else }}1.2.5{{- end }}'
     pullPolicy: '{{ .Values.global.image_pullPolicy }}'