ci: add weekly e2e job against ceph main branch

[Coderxrohan]

Describe what this PR does

1. This PR adds a standalone GitHub Actions workflow that runs ceph-csi E2E tests weekly against the Ceph main branch.
2. The workflow reuses the existing E2E test runner and is configured as non-blocking, ensuring it does not impact PR
   or release CI while helping detect regressions from upstream Ceph changes early.

Is there anything that requires special attention

• No special attention required.
• The workflow is isolated and marked as non-blocking (continue-on-error: true).

Provide any external context for the change, if any.

This follows the goal of catching compatibility issues early when Ceph main
introduces changes that may affect ceph-csi behavior, without impacting
day-to-day development workflows.

Future concerns

If the job proves stable and valuable, it could later be promoted to a more
frequent schedule or integrated with additional reporting/alerting.

Checklist:

• Commit Message Formatting: Commit titles and messages follow guidelines in the developer guide.
• Reviewed the developer guide on Submitting a Pull Request
• Pending release notes updated with breaking and/or notable changes (not required for CI-only change).
• Documentation has been updated, if necessary (not required).
• Unit tests have been added, if necessary (not applicable).
• Integration tests have been added, if necessary (existing E2E reused).

Fixes: #5855

[Coderxrohan]

@Madhu-1
This PR introduces a new standalone GitHub Actions workflow to run E2E tests weekly against the Ceph main branch.
The workflow reuses the existing E2E runner (make e2e) and CI conventions already used in the repo.
(no new test logic was introduced.)

1. It is intentionally isolated and marked non-blocking and
2. does not modify
3. or depend on existing PR,
   -- retest,
   -- or release workflows.

[nixpanic]

Unfortunately this won't work. The e2e tests require more resources than what GitHub provides for their runners.

You will need to create a new Jenkins job in the ci/centos branch under the jobs/ directory. This will make it possible to run something weekly. In addition to that, you probably need to modify one or more of the scripts in the root directory of the ci/centos branch to use the Ceph main branch (CI builds) to deploy the right version.

https://github.com/ceph/ceph-csi/tree/ci/centos

[Coderxrohan]

Thanks for the guidance. I have implemented the suggested changes; please verify #6020

[Coderxrohan]

@nixpanic
Thanks for the guidance; I’ve moved this to a Jenkins-based weekly job under ci/centos/jobs and updated the pipeline to run against Ceph main as suggested.

All CI checks are running now.
Could you please take a look when you get a chance?
Thank you!

PR: #6020