chore: use stringData for transparency around secrets (hope people don't copy)

charts/influxdb-enterprise/example-secrets.yaml

@@ -2,21 +2,20 @@ apiVersion: v1
 kind: Secret
 metadata:
   name: license
-data:
+stringData:
   json: FAKE LICENSE KEY
 ---
 apiVersion: v1
 kind: Secret
 metadata:
   name: auth
-data:
-  # admin / admin
-  username: YWRtaW4=
-  password: YWRtaW4=
+stringData:
+  username: admin
+  password: admin
 ---
 apiVersion: v1
 kind: Secret
 metadata:
   name: shared-secret
-data:
+stringData:
   secret: MY RANDOM STRING