lint: remove unused BeautifulSoup import, fix black

[terriko]

This fixes the current linting errors from flake8 and black. (Caused because of PRs merged before the updated CI rules went through.)

[codecov-commenter]

Codecov Report

Merging #1307 (9352737) into main (453c7c6) will decrease coverage by 1.42%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #1307      +/-   ##
==========================================
- Coverage   81.16%   79.74%   -1.43%     
==========================================
  Files         264      264              
  Lines        4800     4799       -1     
  Branches      575      575              
==========================================
- Hits         3896     3827      -69     
- Misses        759      821      +62     
- Partials      145      151       +6     

Flag	Coverage Δ
longtests	79.74% <ø> (-1.43%)	⬇️

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Impacted Files	Coverage Δ
test/test_nvd_api.py	100.00% <ø> (ø)
cve_bin_tool/checkers/xml2.py	61.36% <0.00%> (-27.28%)	⬇️
test/test_json.py	68.96% <0.00%> (-20.69%)	⬇️
test/test_scanner.py	61.71% <0.00%> (-12.50%)	⬇️
test/test_cli.py	81.99% <0.00%> (-11.38%)	⬇️
cve_bin_tool/checkers/glibc.py	95.83% <0.00%> (-4.17%)	⬇️
cve_bin_tool/cli.py	75.30% <0.00%> (-3.02%)	⬇️
cve_bin_tool/version_scanner.py	74.30% <0.00%> (-1.39%)	⬇️
cve_bin_tool/cvedb.py	82.42% <0.00%> (-0.61%)	⬇️

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