BBSim imagePullPolicy set to always by default

Change-Id: I3f8975fcf3ec9458ca21270c1f72cb85f0b074a9
diff --git a/bbsim/values.yaml b/bbsim/values.yaml
index 270b7d7..6ef6634 100644
--- a/bbsim/values.yaml
+++ b/bbsim/values.yaml
@@ -43,7 +43,7 @@
 image:
   repository: 'voltha/voltha-bbsim'
   tag: '{{ .Chart.AppVersion }}'
-  pullPolicy: 'IfNotPresent'
+  pullPolicy: 'Always'
 
 global:
   registry: ''