Bump urllib3 from 1.26.15 to 1.26.18

Bumps [urllib3](https://github.com/urllib3/urllib3) from 1.26.15 to 1.26.18.
- [Release notes](https://github.com/urllib3/urllib3/releases)
- [Changelog](https://github.com/urllib3/urllib3/blob/main/CHANGES.rst)
- [Commits](https://github.com/urllib3/urllib3/compare/1.26.15...1.26.18)

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

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

requirements.txt

@@ -50,7 +50,7 @@ starlette==0.23.1
     # via platformio
 tabulate==0.9.0
     # via platformio
-urllib3==1.26.15
+urllib3==1.26.18
     # via requests
 uvicorn==0.20.0
     # via platformio