Migrate Fake Client from gopkg.in/evanphx/json-patch.v4 to github.com/evanphx/json-patch/v5

[kersten]

We would like to request that the Fake Client library be updated from the older gopkg.in/evanphx/json-patch.v4 to github.com/evanphx/json-patch/v5.

The primary motivation for this change is to remove the indirect dependency on github.com/pkg/errors that accompanies version v4. This indirect dependency was removed in json-patch v5.9.11 and has been integrated in controller-runtime since version v0.20.2.

Rationale

• Dependency Cleanup: Upgrading to v5 removes the indirect github.com/pkg/errors dependency, reducing the overall dependency footprint.
• Upstream Compatibility: Aligning with newer releases ensures compatibility and support for future bug fixes and features.
• Consistency: As controller-runtime is already using newer versions, matching these library versions helps maintain consistency.

Proposal

1. Update the import statement in pkg/client/fake/client.go from gopkg.in/evanphx/json-patch.v4 to github.com/evanphx/json-patch/v5.
2. Remove the direct v4 dependency entry from go.mod in favor of the v5 version, ensuring no regression in functionality.
3. Validate that existing tests pass and confirm there are no breaking changes.

Please let us know if you have any questions or need more details. Thank you for considering this request.

[kersten]

I created a PR for it: #3118