Fix rm/cp flag order in hack/fetch-releases.sh for macOS compatibility

[jkhelil]

Changes

Submitter Checklist

These are the criteria that every PR should meet, please check them off as you
review them:

• Run make test lint before submitting a PR
• Includes tests (if functionality changed/added)
• Includes docs (if user facing)
• Commit messages follow commit message best practices

See the contribution guide for more details.

Release Notes

NONE

[tekton-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by:
To complete the pull request process, please assign savitaashture after the PR has been reviewed.
You can assign the PR to them by writing /assign @savitaashture in a comment when ready.

The full list of commands accepted by this bot can be found here.

Details

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment