tests: fix http-bad-server expected errors for python 3.10 (issue6643)
The format of the error message changed with this version of Python.
This also removes obsolete Python 3 checks.
docutils
dulwich
# Needed by the release note tooling
fuzzywuzzy
keyring
pygit2
pygments
# Needed by the phabricator tests
pytest-vcr
# Need to list explicitly so dependency gets pulled in when
# not running on Windows.
pywin32-ctypes
windows-curses