Changes

This pull request introduces support for drafting Tekton releases using artifacts stored in Oracle Cloud Storage (OCI), in addition to the existing GitHub-based workflow. The changes include:

• Documentation update for using the new release-draft-oci pipeline to draft releases from Oracle Cloud Storage buckets, including instructions for configuring credentials and bucket paths in tekton/resources/release/README.md.
• Added a new Tekton pipeline (release-draft-oci) and supporting task (create-draft-release-oci) in tekton/resources/release/base/github_release_oci.yaml to automate the process of downloading release manifests from OCI, generating release notes, and creating GitHub draft releases.
• Added new Task (prerelease-checks-oci.yaml) that checks for presence of manifets version in oci bucket. The main consideration for pipelines consuming this task is users MUST pass the workspace reference to secret that includes the oci credentials for the cli to connect to the cluster.

    - name: precheck
      runAfter: [git-clone]
      taskRef:
        name:prerelease-checks-oci
      params:
        - name: package
          value: $(params.package)
        - name: versionTag
          value: $(params.versionTag)
        - name: releaseBucket
          value: $(params.releaseBucket)/$(params.repoName)
      workspaces:
        - name: source-to-release
          workspace: workarea
          subPath: git
        - name: oci-credentials
          workspace: release-secret

• Updated tekton/resources/release/base/kustomization.yaml to include the new github_release_oci.yaml resource, ensuring the new pipeline and task are deployed.

/kind misc

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