Bump urllib3 from 1.26.5 to 1.26.17 in /sourcedocs

Bumps [urllib3](https://github.com/urllib3/urllib3) from 1.26.5 to 1.26.17.
- [Release notes](https://github.com/urllib3/urllib3/releases)
- [Changelog](https://github.com/urllib3/urllib3/blob/main/CHANGES.rst)
- [Commits](urllib3/urllib3@1.26.5...1.26.17)

---
updated-dependencies:
- dependency-name: urllib3
  dependency-type: indirect
...

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

sourcedocs/requirements.txt

@@ -35,7 +35,7 @@ requests==2.31.0
 snowballstemmer==2.1.0
     # via sphinx
 sphinx==4.1.1
-    # via -r sourcedocs/requirements.in
+    # via -r requirements.in
 sphinxcontrib-applehelp==1.0.2
     # via sphinx
 sphinxcontrib-devhelp==1.0.2
@@ -48,7 +48,7 @@ sphinxcontrib-qthelp==1.0.3
     # via sphinx
 sphinxcontrib-serializinghtml==1.1.5
     # via sphinx
-urllib3==1.26.5
+urllib3==1.26.17
     # via requests
 
 # The following packages are considered to be unsafe in a requirements file: