ci: Allow testing PRs targetting release branches

[rm3l]

Description of the change

PRs (like #80) targetting release branches fail because the linter is configured to detect Chart changes compared to the main branch.

Existing or Associated Issue(s)

https://github.com/redhat-developer/rhdh-chart/actions/runs/13111112811/job/36575072460?pr=80

Additional Information

Checklist

• Chart version bumped in Chart.yaml according to semver.
• Variables are documented in the values.yaml and added to the README.md. The pre-commit utility can be used to generate the necessary content. Use pre-commit run -a to apply changes.
• JSON Schema template updated and re-generated the raw schema via pre-commit hook.
• List tests pass for Chart using the Chart Testing tool and the ct lint command.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[rm3l]

/cherry-pick release-1.3
/cherry-pick release-1.4

[openshift-cherrypick-robot]

@rm3l: once the present PR merges, I will cherry-pick it on top of release-1.3, release-1.4 in new PRs and assign them to you.

In response to this:

/cherry-pick release-1.3
/cherry-pick release-1.4

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[openshift-cherrypick-robot]

@rm3l: new pull request created: #84

In response to this:

/cherry-pick release-1.3
/cherry-pick release-1.4

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[openshift-cherrypick-robot]

@rm3l: new pull request created: #85

In response to this:

/cherry-pick release-1.3
/cherry-pick release-1.4

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.