Lib/urllib/request.py: digest algorithm should be case insensitive

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2021-01-05.15:35:06.069>
labels = ['type-bug', '3.8', '3.9', '3.10', '3.7', 'library']
title = 'Lib/urllib/request.py: digest algorithm should be case insensitive'
updated_at = <Date 2021-01-05.16:00:08.371>
user = 'https://github.com/tardyp'

bugs.python.org fields:

activity = <Date 2021-01-05.16:00:08.371>
actor = 'Pierre.Tardy'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2021-01-05.15:35:06.069>
creator = 'Pierre.Tardy'
dependencies = []
files = []
hgrepos = []
issue_num = 42833
keywords = []
message_count = 1.0
messages = ['384409']
nosy_count = 1.0
nosy_names = ['Pierre.Tardy']
pr_nums = ['24122']
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue42833'
versions = ['Python 3.6', 'Python 3.7', 'Python 3.8', 'Python 3.9', 'Python 3.10']