Bump urllib3 from 1.26.13 to 1.26.19 in /include/json/docs/mkdocs

Bumps [urllib3](https://github.com/urllib3/urllib3) from 1.26.13 to 1.26.19.
- [Release notes](https://github.com/urllib3/urllib3/releases)
- [Changelog](https://github.com/urllib3/urllib3/blob/1.26.19/CHANGES.rst)
- [Commits](urllib3/urllib3@1.26.13...1.26.19)

---
updated-dependencies:
- dependency-name: urllib3
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

include/json/docs/mkdocs/requirements.txt

@@ -44,6 +44,6 @@ six==1.16.0
 smmap==5.0.0
 tornado==6.2
 tqdm==4.64.1
-urllib3==1.26.13
+urllib3==1.26.19
 watchdog==2.2.0
 zipp==3.11.0