[3.8] bpo-42967: only use '&' as a query string separator (GH-24297) (#24529)

[3.8] bpo-42967: only use '&' as a query string separator (GH-24297)  (#24529)

* bpo-42967: only use '&' as a query string separator (#24297)

bpo-42967: [security] Address a web cache-poisoning issue reported in
urllib.parse.parse_qsl().

urllib.parse will only us "&" as query string separator by default
instead of both ";" and "&" as allowed in earlier versions. An optional
argument seperator with default value "&" is added to specify the
separator.

Co-authored-by: Éric Araujo <merwok@netwok.org>
Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com>
Co-authored-by: Ken Jin <28750310+Fidget-Spinner@users.noreply.github.com>
Co-authored-by: Éric Araujo <merwok@netwok.org>
(cherry picked from commit fcbe0cb04d35189401c0c880ebfb4311e952d776)

* [3.8] bpo-42967: only use '&' as a query string separator (GH-24297)

bpo-42967: [security] Address a web cache-poisoning issue reported in urllib.parse.parse_qsl().

urllib.parse will only us "&" as query string separator by default instead of both ";" and "&" as allowed in earlier versions. An optional argument seperator with default value "&" is added to specify the separator.

Co-authored-by: Éric Araujo <merwok@netwok.org>
Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com>
Co-authored-by: Ken Jin <28750310+Fidget-Spinner@users.noreply.github.com>
Co-authored-by: Éric Araujo <merwok@netwok.org>.
(cherry picked from commit fcbe0cb04d35189401c0c880ebfb4311e952d776)

Co-authored-by: Adam Goldschmidt <adamgold7@gmail.com>
* Update correct version information.

* fix docs and make logic clearer

Co-authored-by: Adam Goldschmidt <adamgold7@gmail.com>
Co-authored-by: Fidget-Spinner <28750310+Fidget-Spinner@users.noreply.github.com>