Update tf job examples to tf v2

[YosiElias]

What this PR does / why we need it:
Update TFjob examples to TF v2

Which issue(s) this PR fixes (optional, in Fixes #<issue number>, #<issue number>, ... format, will close the issue(s) when PR gets merged):
Fixes #2015

Checklist:

• Docs included if any changes are user facing

[google-oss-prow]

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[coveralls]

Pull Request Test Coverage Report for Build 11046684566

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

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Totals
Change from base Build 11001381410:	0.0%
Covered Lines:	66
Relevant Lines:	66

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💛 - Coveralls

[YosiElias]

Hi @alongzhi, I saw you added ppc64le images before.
In order to support ppc64le I need base image of TF-v2 to replace this image - ibmcom/tensorflow-ppc64le:1.13.1 that used in: examples/tensorflow/dist-mnist/Dockerfile.ppc64le and examples/tensorflow/mnist_with_summaries/Dockerfile.ppc64le.

Can you pls support this image? otherwise just let me know and I'll remove this Dockerfile.ppc64le since the source code support only TF-v2 now..

@JosepSampe @ckadner Do you know who can support this image from IBM?

@andreyvelich - FYI

[andreyvelich]

@alongzhi Are you planning to continue support powerPC images in Training Operator ?
Otherwise, we will remove them.
cc @kubeflow/wg-training-leads