Bump ipython from 7.11.1 to 7.21.0

Bumps [ipython](https://github.com/ipython/ipython) from 7.11.1 to 7.21.0.
- [Release notes](https://github.com/ipython/ipython/releases)
- [Commits](ipython/ipython@7.11.1...7.21.0)

Signed-off-by: dependabot[bot] <support@github.com>

requirements.txt

@@ -1,6 +1,6 @@
 boto3==1.17.17
 dnspython==2.1.0
-ipython==7.11.1
+ipython==7.21.0
 ipdb==0.13.5
 libvirt-python==7.0.0
 pre-commit==2.11.0