Fixed formatting and added missing 'data' key to overrides yaml (#216)

manuscript/kubernetes/sealed-secrets.md

@@ -117,6 +117,7 @@ Now we're into the sealed-secrets-specific YAMLs. First, we create a ConfigMap,
       creationTimestamp: null
       name: sealed-secrets-helm-chart-value-overrides
       namespace: sealed-secrets
+    data:
       values.yaml: |-
         image:
         repository: quay.io/bitnami/sealed-secrets-controller