v2.9.0-rc4

What's Changed

• Removed not needed information in the sha256sum.txt file in release by @enrichman in #368
• [v2.9] add codeowners file by @JonCrowther in #369
• [v2.9] Use Rancher org FOSSA secret by @enrichman in #373
• [v2.9][forwardport] Small refactor (error messages) by @enrichman in #375

Full Changelog: v2.9.0-rc3...v2.9.0-rc4