Fix github RSA key error

[uchar]

Changes

Fix for https://github.com/game-ci/unity-builder/issues/525

Checklist

• [x] Read the contribution guide and accept the code of conduct
• [x] Readme (updated or not needed)
• [x] Tests (added, updated or not needed)

[github-actions[bot]]

[webbertakken]

Excellent. Thank you for your contribution!