repomd_parser update + bzip2 support

[felixsch]

Update repomd_parser to 1.1.0

• Add support for bzip2 compressed repositories
• Align with new repomd_parser interface

How to test this pull request:

# Have a running RMT with this branch checked out
$ bin/rmt-cli repos custom add https://rpms.remirepo.net/enterprise/8/php80/x86_64/ php80
$ bin/rmt-cli mirror repository php80
# expect: Mirroring works fine

thank you very much! :rocket: