With v0.12.0:

File Input is not supported as documented:

Warning: Unexpected input(s) 'file', valid inputs are ['path', 'image', 'registry-username', 'registry-password', 'format', 'github-token', 'artifact-name', 'output-file', 'syft-version', 'dependency-snapshot', 'upload-artifact', 'upload-release-assets']

ex:

    - uses: anchore/sbom-action@v0
      with: 
        file: ./path/to/target/app.jar
        dependency-snapshot: true

ref: #357