Fix Helm chart linting error by adding newline at end of values.yaml

The chart-testing linter requires a newline character at the end of YAML files.
Added the missing newline to resolve the 'new-line-at-end-of-file' error.

Signed-off-by: josecsotomorales <[email protected]>

Author: josecsotomorales

charts/spark-operator-chart/values.yaml

@@ -481,4 +481,3 @@ certManager:
   # See [cert-manager.io/v1.Certificate](https://cert-manager.io/docs/reference/api-docs/#cert-manager.io/v1.Certificate).
   # @default -- 1/3 of issued certificate’s lifetime.
   renewBefore: ""
-