fix lambda ui tag : string needed instead on int

Author: kwiatekus

resources/core/charts/kubeless/charts/lambdas-ui/values.yaml

@@ -4,7 +4,7 @@
 replicaCount: 1
 image:
   name: lambda
-  tag: 6951554
+  tag: '6951554'
   pullPolicy: IfNotPresent
 service:
   name: nginx