Tar path traversal in stereoscope when processing OCI tar archives

stereoscope is a go library for processing container images and simulating a squash filesystem. Prior to version 0.0.1, it is possible to craft an OCI tar archive that, when stereoscope attempts to unarchive the contents, will result in writing to paths outside of the unarchive temporary directory. Specifically, use of github.com/anchore/stereoscope/pkg/file.UntarToDirectory() function, the github.com/anchore/stereoscope/pkg/image/oci.TarballImageProvider struct, or the higher level github.com/anchore/stereoscope/pkg/image.Image.Read() function express this vulnerability. As a workaround, if you are using the OCI archive as input into stereoscope then you can switch to using an OCI layout by unarchiving the tar archive and provide the unarchived directory to stereoscope.