Link to DCO guidance in PR workflow is broken.

<!-- Make sure that you visit our User Guide at https://kubevirt.io/user-guide. --> **Description**: After submitting a PR, there is a workflow generated which provides a clickable link to "DCO" which directs the user to https://github.com/kubevirt/kubevirt.github.io/blob/main/CONTRIBUTING.md - and that file does not exist. **What you expected**: I was hoping to be redirected to the CONTRIBUTING guide so that I could learn what I should have done differently. **URL**: You can find the broken DCO link in my recent PR: https://github.com/kubevirt/kubevirt.github.io/pull/999 which leads to: https://github.com/kubevirt/kubevirt.github.io/blob/main/CONTRIBUTING.md **Additional context**: Add any other context about the issue here.