Fix GH workflow to clone dsp-developers/odh-manifests fork

[DharmitD]

The issue resolved by this Pull Request:

Resolves #178

Description of your changes:

Updating the workflow to create a sync PR into odh-manifests, to have the dsp-developers' fork cloned instead of opendatahub-io/odh-manifests.

Testing instructions

Checklist

• The commits are squashed in a cohesive manner and have meaningful messages.
• Testing instructions have been added in the PR body (for PRs involving changes that are not immediately obvious).
• The developer has manually tested the changes and verified that the changes work

[openshift-ci]

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[dsp-developers]

A new image has been built to help with testing out this PR: quay.io/opendatahub/data-science-pipelines-operator:pr-257