Leases cleanup add security context

[ybelMekk]

Description of the change

securityContxect to cleanup-leases job

• In a cluster with https://kubernetes.io/docs/reference/access-authn-authz/validating-admission-policy/ or other similar best practice policies, the lease job does not clean up, as it fails to be created, output similar errors:

run-as-non-root: 'validation error: Running as root is not allowed. Either the field..

This also relates to issue listed, leases dont get cleaned up the application fails to start if re-deployed.

Existing or Associated Issue(s)

https://github.com/sigstore/helm-charts/issues/217#issuecomment-1160155615

Additional Information

Add podSecurity context and security context to values.yaml and corresponding cleanup-lease job.

Checklist

• [x] Chart version bumped in Chart.yaml according to semver. Where applicable, update and bump the versions in any associated umbrella chart
• [x] Variables are documented in the values.yaml and added to the README.md. The helm-docs utility can be used to generate the necessary content. Use helm-docs --dry-run to preview the content.
• [ ] JSON Schema generated.
• [x] List tests pass for Chart using the Chart Testing tool and the ct lint command.