Update README.md

[johnybradshaw]

In the encrypted StorageClass example the namespace set in the Secret and the namespace referenced by the StorageClass do not match. This will cause pods to fail to deploy.

Namespace mismatch, was default, should be csi-encrypt-example

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• [x] Have you removed all sensitive information, including but not limited to access keys and passwords?
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[luthermonson]

sorry about that! nice catch