fix: tools/c7n_sphinxext/requirements.txt to reduce vulnerabilities

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-CERTIFI-5805047
- https://snyk.io/vuln/SNYK-PYTHON-MARKDOWNITPY-3330239
- https://snyk.io/vuln/SNYK-PYTHON-MARKDOWNITPY-3330240
- https://snyk.io/vuln/SNYK-PYTHON-PYGMENTS-5750273
- https://snyk.io/vuln/SNYK-PYTHON-REQUESTS-5595532
- https://snyk.io/vuln/SNYK-PYTHON-URLLIB3-5926907
- https://snyk.io/vuln/SNYK-PYTHON-URLLIB3-6002459

tools/c7n_sphinxext/requirements.txt

@@ -1,6 +1,6 @@
 alabaster==0.7.12 ; python_version >= "3.7" and python_version < "4.0"
 babel==2.11.0 ; python_version >= "3.7" and python_version < "4.0"
-certifi==2022.12.7 ; python_version >= "3.7" and python_version < "4.0"
+certifi==2023.7.22 ; python_version >= "3.7" and python_version < "4.0"
 charset-normalizer==2.0.12 ; python_version >= "3.7" and python_version < "4.0"
 click==8.1.3 ; python_version >= "3.7" and python_version < "4.0"
 colorama==0.4.6 ; python_version >= "3.7" and python_version < "4.0" and sys_platform == "win32" or python_version >= "3.7" and python_version < "4.0" and platform_system == "Windows"
@@ -10,18 +10,18 @@ idna==3.4 ; python_version >= "3.7" and python_version < "4.0"
 imagesize==1.4.1 ; python_version >= "3.7" and python_version < "4.0"
 importlib-metadata==4.13.0 ; python_version >= "3.7" and python_version < "3.10"
 jinja2==3.1.2 ; python_version >= "3.7" and python_version < "4.0"
-markdown-it-py==2.1.0 ; python_version >= "3.7" and python_version < "4.0"
+markdown-it-py==2.2.0 ; python_version >= "3.7" and python_version < "4.0"
 markdown==3.0.1 ; python_version >= "3.7" and python_version < "4.0"
 markupsafe==2.1.1 ; python_version >= "3.7" and python_version < "4.0"
 mdit-py-plugins==0.3.3 ; python_version >= "3.7" and python_version < "4.0"
 mdurl==0.1.2 ; python_version >= "3.7" and python_version < "4.0"
 myst-parser==0.18.1 ; python_version >= "3.7" and python_version < "4.0"
 packaging==22.0 ; python_version >= "3.7" and python_version < "4.0"
-pygments==2.13.0 ; python_version >= "3.7" and python_version < "4.0"
+pygments==2.15.0 ; python_version >= "3.7" and python_version < "4.0"
 pytz==2022.6 ; python_version >= "3.7" and python_version < "4.0"
 pyyaml==6.0 ; python_version >= "3.7" and python_version < "4.0"
 recommonmark==0.6.0 ; python_version >= "3.7" and python_version < "4.0"
-requests==2.27.1 ; python_version >= "3.7" and python_version < "4.0"
+requests==2.31.0 ; python_version >= "3.7" and python_version < "4.0"
 snowballstemmer==2.2.0 ; python_version >= "3.7" and python_version < "4.0"
 sphinx-markdown-tables==0.0.12 ; python_version >= "3.7" and python_version < "4.0"
 sphinx-rtd-theme==1.1.1 ; python_version >= "3.7" and python_version < "4.0"
@@ -33,5 +33,5 @@ sphinxcontrib-jsmath==1.0.1 ; python_version >= "3.7" and python_version < "4.0"
 sphinxcontrib-qthelp==1.0.3 ; python_version >= "3.7" and python_version < "4.0"
 sphinxcontrib-serializinghtml==1.1.5 ; python_version >= "3.7" and python_version < "4.0"
 typing-extensions==4.4.0 ; python_version >= "3.7" and python_version < "4.0"
-urllib3==1.26.13 ; python_version >= "3.7" and python_version < "4.0"
+urllib3==1.26.18 ; python_version >= "3.7" and python_version < "4.0"
 zipp==3.11.0 ; python_version >= "3.7" and python_version < "3.10"