Bump ipython from 7.4.0 to 7.21.0
Bump ipython from 7.4.0 to 7.21.0

Bumps [ipython](https://github.com/ipython/ipython) from 7.4.0 to 7.21.0.
- [Release notes](https://github.com/ipython/ipython/releases)
- [Commits](https://github.com/ipython/ipython/compare/7.4.0...7.21.0)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>
DemocracyClub/yournextrepresentative,DemocracyClub/yournextrepresentative,DemocracyClub/yournextrepresentative