Bump tensorflow from 1.14.0 to 1.15.4 in /docs/samples/explanation/aix/mnist (#1107)
Bump tensorflow from 1.14.0 to 1.15.4 in /docs/samples/explanation/aix/mnist (#1107)

Bumps [tensorflow](https://github.com/tensorflow/tensorflow) from 1.14.0 to 1.15.4.
- [Release notes](https://github.com/tensorflow/tensorflow/releases)
- [Changelog](https://github.com/tensorflow/tensorflow/blob/master/RELEASE.md)
- [Commits](https://github.com/tensorflow/tensorflow/compare/v1.14.0...v1.15.4)

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Co-authored-by: dependabot[bot] <1c358da00a777d4e9898c1280ab801e2df165188@users.noreply.github.com>
kubeflow/kfserving-lts,kubeflow/kfserving-lts,kubeflow/kfserving-lts,kubeflow/kfserving-lts,kubeflow/kfserving-lts,kubeflow/kfserving-lts