Fix sample for Ingress TLS

[javiercr]

v1beta1.IngressSpec expects an v1beta1.IngressTLS array.

Without this change executing the code in the example will return this error:

error validating "ingress.yml": error validating data: expected type array, for field spec.tls, got map; if you choose to ignore these errors, turn validation off with --validate=false

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[javiercr]

I signed it!

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CLAs look good, thanks!

[johndmulhausen]

Thanks @javiercr !