Using latest released version for different components and update voltha-stack chart.

Change-Id: I383927d4c691859ca33a73d384b633435eed15e7
diff --git a/voltha/values.yaml b/voltha/values.yaml
index 0d6671d..c88888e 100644
--- a/voltha/values.yaml
+++ b/voltha/values.yaml
@@ -93,13 +93,13 @@
   ofagent:
     registry: '{{ .Values.global.image_registry }}'
     repository: '{{ .Values.global.image_org }}voltha-ofagent-go'
-    tag: '{{- if hasKey .Values.global "image_tag" }}{{- if .Values.global.image_tag }}{{ .Values.global.image_tag }}{{- else }}1.5.2{{- end }}{{- else }}1.5.2{{- end }}'
+    tag: '{{- if hasKey .Values.global "image_tag" }}{{- if .Values.global.image_tag }}{{ .Values.global.image_tag }}{{- else }}1.6.1{{- end }}{{- else }}1.6.1{{- end }}'
     pullPolicy: '{{ .Values.global.image_pullPolicy }}'
 
   rw_core:
     registry: '{{ .Values.global.image_registry }}'
     repository: '{{ .Values.global.image_org }}voltha-rw-core'
-    tag: '{{- if hasKey .Values.global "image_tag" }}{{- if .Values.global.image_tag }}{{ .Values.global.image_tag }}{{- else }}2.8.1{{- end }}{{- else }}2.8.1{{- end }}'
+    tag: '{{- if hasKey .Values.global "image_tag" }}{{- if .Values.global.image_tag }}{{ .Values.global.image_tag }}{{- else }}2.9.1{{- end }}{{- else }}2.9.1{{- end }}'
     pullPolicy: '{{ .Values.global.image_pullPolicy }}'
 
 ingress: