Add support for zstd RPM files

[egibs]

I noticed that we weren't extracting zstd RPM files:

unable to process /tmp/malcontent-3727400076/srv/gitlab/vendor/bundle/ruby/3.2.0/gems/arr-pm-0.0.12/spec/fixtures/pagure-mirror-5.13.2-5.fc35.noarch.rpm: extract to temp: failed to extract /tmp/malcontent-3727400076/srv/gitlab/vendor/bundle/ruby/3.2.0/gems/arr-pm-0.0.12/spec/fixtures/pagure-mirror-5.13.2-5.fc35.noarch.rpm: unsupported compression format: zstd

This PR adds another case statement to allow for these files to be extracted:

🔎 Scanning "~/Downloads/gitlab-rails/srv/gitlab/vendor/bundle/ruby/3.2.0/gems/arr-pm-0.0.12/spec/fixtures/pagure-mirror-5.13.2-5.fc35.noarch.rpm"
Matches for ~/Downloads/gitlab-rails/srv/gitlab/vendor/bundle/ruby/3.2.0/gems/arr-pm-0.0.12/spec/fixtures/pagure-mirror-5.13.2-5.fc35.noarch.rpm ∴ /usr/lib/systemd/system/pagure_mirror.service [LOW] (4 rules):
etc_path [LOW] (1 string):
- /etc/pagure/pagure.cfg
https_url [LOW] (1 string):
- https://pagure.io/pagure
ref_systemd [LOW] (1 string):
- systemd
usr_bin_path [LOW] (1 string):
- /usr/bin/celery-3