[DOC] Sample CUDA dockerfile should be public or a simple static file

[vamseeyarla]

Report incorrect documentation

Location of incorrect documentation
https://nvidia.github.io/spark-rapids/docs/get-started/getting-started.html#running-on-kubernetes

Describe the problems or issues found in the documentation
Sample CUDA dockerfile should be public or a simple static file

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Suggested fix for documentation
A static file or a public google drive link helps.

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