Run apt-update before installing skopeo for prepare openshift bundle (#419)

# Summary

Before actually generating the OLM bundle we try to run
`setup_prepare_openshift_bundles.sh` that installs `skopeo` using apt.
But the local apt repos are not updated and because of that the `skopeo`
installation fails. This PR fixes that by running `apt update` before
installing `skopeo`.

More about this can be found
[here](https://mongodb.slack.com/archives/CGLP6R2PQ/p1757074525568919?thread_ts=1756988558.169489&cid=CGLP6R2PQ).

## Proof of Work

After this change the task passed.

## Checklist

- [ ] Have you linked a jira ticket and/or is the ticket in the title?
- [x] Have you checked whether your jira ticket required DOCSP changes?
- [x] Have you added changelog file?
    - use `skip-changelog` label if not needed
- refer to [Changelog files and Release
Notes](https://github.com/mongodb/mongodb-kubernetes/blob/master/CONTRIBUTING.md#changelog-files-and-release-notes)
section in CONTRIBUTING.md for more details

Author: viveksinghggits

scripts/evergreen/setup_prepare_openshift_bundles.sh

@@ -22,6 +22,7 @@ download_and_install_binary "${PROJECT_DIR:-.}/bin" operator-manifest-tools "htt
 if [[ "${OS}" == "darwin" ]]; then
   brew install skopeo
 else
+  sudo apt-get update
   sudo apt install -y skopeo
 fi