No lintable files found at paths

I am upgrading my CI from 0.32.0 to the latest. I use the norio-nomura Docker images.

The step in the CI is just swiftlint lint --strict "$CI_PROJECT_DIR". When I change my container to norionomura/swiftlint:0.46.5_swift-5 I see the following error in the output.

Linting Swift files at paths /builds/buildbot/Project
Error: No lintable files found at paths: '/builds/buildbot/Project'

I have found that 0.32.0, 0.33.0, 0.34.0, 0.35.0 all work. From 0.36.0 onward I get that error above.

I really am at a loss to troubleshoot this. Any suggestions on how to move forward?