Bump more-itertools from 8.2.0 to 8.4.0

Bumps more-itertools from 8.2.0 to 8.4.0.

Release notes

Sourced from more-itertools's releases.

Version 8.4.0

See the changelog for details.

Version 8.3.0

See the release notes for details.

Commits

• c65a3de Version 8.4.0 (#435)
• 8dabf1a Test exception chaining
• 0b64a77 Merge branch 'cool-RR-2020-06-11-raise-from'
• 739a8fa Fix exception causes
• ac26d86 is_sorted function (#434)
• 94bbc88 Remove unneeded tuple(exceptions)call (#433)
• 5eaff74 Merge mark_ends
• a7a5b9a Merge branch 'kalekundert-master'
• 7c08fc9 Merge branch 'master' of https://github.com/kalekundert/more-itertools into k...
• 35f4cc5 Fix flake8 issues.
• Additional commits viewable in compare view