Bump urllib3 from 1.26.5 to 1.26.18 in /boilerplates/dash

Bumps [urllib3](https://github.com/urllib3/urllib3) from 1.26.5 to 1.26.18.
- [Release notes](https://github.com/urllib3/urllib3/releases)
- [Changelog](https://github.com/urllib3/urllib3/blob/main/CHANGES.rst)
- [Commits](urllib3/urllib3@1.26.5...1.26.18)

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

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

boilerplates/dash/requirements.txt

@@ -23,7 +23,7 @@ requests==2.31.0
 retrying==1.3.3
 six==1.11.0
 traitlets==4.3.2
-urllib3==1.26.5
+urllib3==1.26.18
 Werkzeug==2.3.8
 numpy==1.22.0
 pandas==0.25.3