avoid helm lint errors when adding annotations in a composable chart … (#3025)

* avoid helm lint errors when adding annotations in a composable chart values.yaml

without this we get a helm lint warning of:
`warning: destination for annotations is a table. Ignoring non-table value <nil>`

* Incrementing chart version

stable/sonatype-nexus/Chart.yaml

@@ -1,5 +1,5 @@
 name: sonatype-nexus
-version: 0.1.4
+version: 0.1.5
 appVersion: 3.5.1
 description: Sonatype Nexus is an open source repository manager
 keywords:

stable/sonatype-nexus/values.yaml

@@ -17,7 +17,7 @@ service:
   livenessProbe:
     initialDelaySeconds: 30
     periodSeconds: 30
-  annotations:
+  annotations: {}
   # foo.io/bar: "true"
 ingress:
   enabled: false