Unpack an archive.
`filename` is the name of the archive.
`extract_dir` is the name of the target directory, where the archive
is unpacked. If not provided, the current working directory is used.
`format` is the archive format: one of "zip", "tar", "gztar", "bztar",
"xztar", or "zstdtar". Or any other registered format. If not provided,
unpack_archive will use the filename extension and see if an unpacker
was registered for that extension.
In case none is found, a ValueError is raised.
If `filter` is given, it is passed to the underlying
extraction function.