Update ipython[notebook] requirement in /_requirements

Updates the requirements on [ipython[notebook]](https://github.com/ipython/ipython) to permit the latest version.
- [Release notes](https://github.com/ipython/ipython/releases)
- [Commits](ipython/ipython@8.0.0...8.19.0)

---
updated-dependencies:
- dependency-name: ipython[notebook]
  dependency-type: direct:production
...

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

Author: dependabot[bot]

Diff for: _requirements/default.txt

@@ -1,6 +1,6 @@
 setuptools>=68.0.0, <68.3.0
 matplotlib>=3.0.0, <3.9.0
-ipython[notebook]>=8.0.0, <8.17.0
+ipython[notebook]>=8.0.0, <8.20.0
 urllib3  # for ipython
 torch>=1.8.1, <2.1.0
 pytorch-lightning>=1.4, <2.1.0