[stable/spinnaker] Fix for wrong minio image tag spec (#20488)

minio image tag can be specified with `minio.image.tag`
instead of `minio.imageTag` as reported on
https://github.com/helm/charts/issues/14250

Signed-off-by: Ryuichi Inagaki <ryuichi.inagaki.24@googlemail.com>

stable/spinnaker/Chart.yaml

@@ -1,7 +1,7 @@
 apiVersion: v1
 description: Open source, multi-cloud continuous delivery platform for releasing software changes with high velocity and confidence.
 name: spinnaker
-version: 1.23.1
+version: 1.23.2
 appVersion: 1.16.2
 home: http://spinnaker.io/
 sources:

stable/spinnaker/values.yaml

@@ -256,7 +256,8 @@ redis:
 # Minio is not exposed publically
 minio:
   enabled: true
-  imageTag: RELEASE.2019-02-13T19-48-27Z
+  image:
+    tag: RELEASE.2018-08-25T01-56-38Z
   serviceType: ClusterIP
   accessKey: spinnakeradmin
   secretKey: spinnakeradmin