- update to version 174:
* Check that we are parsing an actual Debian .buildinfo file, not just
a file with that extension.
(Closes: deb#987994, reproducible-builds/diffoscope#254)
* Support signed .buildinfo files again -- file(1) reports them as
"PGP signed message".
* Make the testsuite pass with file(1) version 5.40.
* Embed some short test fixtures in the test code itself.
* Fix recognition of compressed .xz files with file(1) 5.40.
OBS-URL: https://build.opensuse.org/package/show/devel:languages:python/diffoscope?expand=0&rev=17
