fix: examples/dev_requirements.txt to reduce vulnerabilities

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-CERTIFI-3164749
- https://snyk.io/vuln/SNYK-PYTHON-CERTIFI-5805047
- https://snyk.io/vuln/SNYK-PYTHON-IPYTHON-2348630
- https://snyk.io/vuln/SNYK-PYTHON-JUPYTERCORE-3063766
- https://snyk.io/vuln/SNYK-PYTHON-MISTUNE-2940625
- https://snyk.io/vuln/SNYK-PYTHON-NBCONVERT-2979829
- https://snyk.io/vuln/SNYK-PYTHON-PYGMENTS-1086606
- https://snyk.io/vuln/SNYK-PYTHON-PYGMENTS-1088505
- https://snyk.io/vuln/SNYK-PYTHON-PYGMENTS-5750273
- https://snyk.io/vuln/SNYK-PYTHON-REQUESTS-5595532
- https://snyk.io/vuln/SNYK-PYTHON-SETUPTOOLS-3180412
- https://snyk.io/vuln/SNYK-PYTHON-TORNADO-5537286
- https://snyk.io/vuln/SNYK-PYTHON-TORNADO-5840803
- https://snyk.io/vuln/SNYK-PYTHON-TORNADO-6041512
- https://snyk.io/vuln/SNYK-PYTHON-WHEEL-3180413

examples/dev_requirements.txt

@@ -8,4 +8,14 @@ black-nb
 pypandoc # for markdown reader
 pypandoc_binary # pypandoc pandoc backend
 panflute # for pandoc filters
-jinja2 # for readme generations
+jinja2 # for readme generations
+certifi>=2023.7.22 # not directly required, pinned by Snyk to avoid a vulnerability
+ipython>=7.16.3 # not directly required, pinned by Snyk to avoid a vulnerability
+jupyter-core>=4.11.2 # not directly required, pinned by Snyk to avoid a vulnerability
+mistune>=2.0.3 # not directly required, pinned by Snyk to avoid a vulnerability
+nbconvert>=6.3.0b0 # not directly required, pinned by Snyk to avoid a vulnerability
+pygments>=2.15.0 # not directly required, pinned by Snyk to avoid a vulnerability
+requests>=2.31.0 # not directly required, pinned by Snyk to avoid a vulnerability
+setuptools>=65.5.1 # not directly required, pinned by Snyk to avoid a vulnerability
+tornado>=6.3.3 # not directly required, pinned by Snyk to avoid a vulnerability
+wheel>=0.38.0 # not directly required, pinned by Snyk to avoid a vulnerability