Bump github.com/IBM/go-sdk-core/v5 from 5.15.1 to 5.15.3

Bumps [github.com/IBM/go-sdk-core/v5](https://github.com/IBM/go-sdk-core) from 5.15.1 to 5.15.3.
- [Release notes](https://github.com/IBM/go-sdk-core/releases)
- [Changelog](https://github.com/IBM/go-sdk-core/blob/main/CHANGELOG.md)
- [Commits](IBM/go-sdk-core@v5.15.1...v5.15.3)

---
updated-dependencies:
- dependency-name: github.com/IBM/go-sdk-core/v5
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>