Bump ipython from 7.31.0 to 8.0.0 (AtsushiSakai#627)

Bumps [ipython](https://github.com/ipython/ipython) from 7.31.0 to 8.0.0.
- [Release notes](https://github.com/ipython/ipython/releases)
- [Commits](ipython/ipython@7.31.0...8.0.0)

---
updated-dependencies:
- dependency-name: ipython
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

docs/requirements.txt

@@ -1,3 +1,3 @@
 sphinx < 5.0 # For sphinx documentation
 sphinx_rtd_theme == 1.0.0
-IPython == 7.31.0 # For sphinx documentation
+IPython == 8.0.0 # For sphinx documentation

requirements.txt

@@ -9,4 +9,4 @@ mypy == 0.931 # For unit test
 flake8 == 4.0.1 # For unit test
 sphinx == 4.3.2 # For sphinx documentation
 sphinx_rtd_theme == 1.0.0
-IPython == 7.31.0 # For sphinx documentation
+IPython == 8.0.0 # For sphinx documentation