Fix paths filtering in the case of empty filter

[IlyaKhD]

Practical Value

The paths is not required, but if not specified, empty list of files returned.

Before

    - uses: DevExpress/github-actions/get-changed-files@v1
      with:
        gh-token: XXX
        paths: '**/*'
        output: XXX

After

    - uses: DevExpress/github-actions/get-changed-files@v1
      with:
        gh-token: XXX
        output: XXX

[IlyaKhD]

Recreated as #26