fix: requirements.txt to reduce vulnerabilities

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-FONTTOOLS-6133203
- https://snyk.io/vuln/SNYK-PYTHON-MKDOCSMATERIAL-7856160
- https://snyk.io/vuln/SNYK-PYTHON-PILLOW-5918878
- https://snyk.io/vuln/SNYK-PYTHON-PILLOW-6043904
- https://snyk.io/vuln/SNYK-PYTHON-PILLOW-6182918
- https://snyk.io/vuln/SNYK-PYTHON-PILLOW-6219984
- https://snyk.io/vuln/SNYK-PYTHON-PILLOW-6219986
- https://snyk.io/vuln/SNYK-PYTHON-PILLOW-6514866
- https://snyk.io/vuln/SNYK-PYTHON-REQUESTS-6928867
- https://snyk.io/vuln/SNYK-PYTHON-URLLIB3-7267250
- https://snyk.io/vuln/SNYK-PYTHON-ZIPP-7430899

requirements.txt

@@ -1,5 +1,5 @@
 mkdocs==1.4.2
-mkdocs-material==9.0.2
+mkdocs-material==9.5.32
 mkdocs-material-extensions==1.1.1
 mkdocs-minify-plugin==0.6.2
 mike==1.1.2
@@ -8,3 +8,7 @@ mkdocs-git-revision-date-localized-plugin==1.1.0
 mkdocs-macros-plugin==0.7.0
 mkdocs-with-pdf==0.9.3
 zipp>=3.19.1 # not directly required, pinned by Snyk to avoid a vulnerability
+fonttools>=4.43.0 # not directly required, pinned by Snyk to avoid a vulnerability
+pillow>=10.3.0 # not directly required, pinned by Snyk to avoid a vulnerability
+requests>=2.32.2 # not directly required, pinned by Snyk to avoid a vulnerability
+urllib3>=2.2.2 # not directly required, pinned by Snyk to avoid a vulnerability