fix: docs/requirements.txt to reduce vulnerabilities

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-JUPYTERLAB-16425771
- https://snyk.io/vuln/SNYK-PYTHON-JUPYTERSERVER-16425696
- https://snyk.io/vuln/SNYK-PYTHON-JUPYTERSERVER-16425697
- https://snyk.io/vuln/SNYK-PYTHON-JUPYTERSERVER-16425698
- https://snyk.io/vuln/SNYK-PYTHON-JUPYTERSERVER-16425699
- https://snyk.io/vuln/SNYK-PYTHON-MISTUNE-16438944
- https://snyk.io/vuln/SNYK-PYTHON-PILLOW-16419304
- https://snyk.io/vuln/SNYK-PYTHON-PILLOW-16419307

Author: snyk-bot

docs/requirements.txt

@@ -15,3 +15,7 @@ pysolr
 nbformat>=4.2.0
 numpy>=1.22.2 # not directly required, pinned by Snyk to avoid a vulnerability
 zipp>=3.19.1 # not directly required, pinned by Snyk to avoid a vulnerability
+jupyterlab>=4.5.7 # not directly required, pinned by Snyk to avoid a vulnerability
+jupyter-server>=2.18.0 # not directly required, pinned by Snyk to avoid a vulnerability
+mistune>=3.2.1 # not directly required, pinned by Snyk to avoid a vulnerability
+pillow>=12.2.0 # not directly required, pinned by Snyk to avoid a vulnerability