add dependabot config script

[davidspek]

Inspired by kubeflow/pipelines#4682 I created a script that will create a config file for depandabot so that it knows what directories to scan. It will scan the repository for files named *ockerfile*, package*.json, *requirements.txt and go.*. It is setup for dockerfiles, npm packages, pip dependencies and gomod at the moment. It is trivial to further customize what folders are selected if further customization is needed. It also parses the closest OWNERS file for a given dependency listing file, and assigns the relevant approvers and adds the relevant reviewers to the PRs it creates.

This is a sibling PR to kubeflow/pipelines#5015, kubeflow/kubeflow#5542, kserve/kserve#1309, kubeflow/arena#403, kubeflow/testing#855, kubeflow/fairing#550, kubeflow/kfp-tekton#432, kubeflow/katib#1420, kubeflow/training-operator#1224, kubeflow/kfp-tekton-backend#28, kubeflow/mpi-operator#319, kubeflow/pytorch-operator#315, kubeflow/metadata#255, kubeflow/xgboost-operator#107, kubeflow/fate-operator#26, kubeflow/mxnet-operator#87, kubeflow/website#2459, kubeflow/kfctl#479, kubeflow/examples#843, kubeflow/code-intelligence#198, GoogleCloudPlatform/kubeflow-distribution#192, kubeflow/common#107, kubeflow/blog#64, kubeflow/kubebench#215, kubeflow/internal-acls#429, kubeflow/community-infra#34 and kubeflow/caffe2-operator#4

I am not yet sure how many PRs will be created with this configuration, as dependabot is not yet finished scanning my fork.

For reference, the PRs that will be created can be found here: https://github.com/DavidSpek/crd-validation/pulls

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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[davidspek]

/assign @carmark

[davidspek]

I am holding the PR to have some control over when it gets merged so that the optional test infra doesn't get overloaded if all the repo's were to merge this at the same time.
/hold