feat(checker): add rhythmbox

[donheshanthaka]

Implement rhythmbox checker

[terriko]

Black has a complaint about test/test_data/rhythmbox.py that you'll need to resolve here.

[terriko]

This one looks ready to go. I'm going to let the windows tests complete before merging, but I'll mark it as approved now so you get the hacktoberfest credit in case you're participating.

[terriko]

Darn, this one is also having windows errors:

 =========================== short test summary info ===========================
FAILED test/test_condensed_downloads.py::test_condensed_downloads - AssertionError: Condensed downloads are not commited
assert False
 +  where False = all(<generator object test_condensed_downloads.<locals>.<genexpr> at 0x0000024A809BE880>)
FAILED test/test_scanner.py::TestScanner::test_version_mapping[rhythmbox-3.4.6-version_strings417] - AssertionError: assert 'rhythmbox' in set()
FAILED test/test_scanner.py::TestScanner::test_version_in_package[http://ftp.fr.debian.org/debian/pool/main/r/rhythmbox/-rhythmbox_3.4.7-1_i386.deb-rhythmbox-3.4.7-other_products851] - AssertionError: rhythmbox not found in rhythmbox_3.4.7-1_i386.deb.
          The checker signature or url may be incorrect.
assert 'rhythmbox' in set()

I'm not sure what's going on here at a glance, but I will go mark this (and the other one) as approved for hacktoberfest in case you need the credit. I don't want to penalize you for trying something harder than a one-line commit if you were hoping to get credit!

[donheshanthaka]

@terriko Thanks a lot, i'll really appreciate you adding the tags, this is the only project that i got the chance to contribute this year. i'm a bit confused on whats causing the windows only fails, but i'm checking on them and will try my best to fix them soon. If you were to find anything related to the cause kindly let me know :)

[donheshanthaka]

Hi, @terriko just wanted to let you know that I don't have access to my computer till Monday, but I will make the necessary changes once I do. giving you an update since you helped me by adding the tags and I would not abandon this and other the two PRs. :)

[terriko]

@donheshanthaka Have a good weekend! I'm actually out dealing with appointments on Monday, so I probably won't come back to poke at these until after you're back, then!