Bump pip from 22.2.1 to 23.3 in /requirements

Bumps [pip](https://github.com/pypa/pip) from 22.2.1 to 23.3.
- [Changelog](https://github.com/pypa/pip/blob/main/NEWS.rst)
- [Commits](https://github.com/pypa/pip/compare/22.2.1...23.3)

---
updated-dependencies:
- dependency-name: pip
  dependency-type: indirect
...
Signed-off-by: dependabot[bot] <support@github.com>

requirements/checkdocs.txt

@@ -111,7 +111,7 @@ zipp==3.8.1
     # via importlib-metadata
 
 # The following packages are considered to be unsafe in a requirements file:
-pip==22.2.1
+pip==23.3
     # via pip-tools
 setuptools==65.5.1
     # via pip-tools

requirements/docs.txt

@@ -111,7 +111,7 @@ zipp==3.8.1
     # via importlib-metadata
 
 # The following packages are considered to be unsafe in a requirements file:
-pip==22.2.1
+pip==23.3
     # via pip-tools
 setuptools==65.5.1
     # via pip-tools