Bump urllib3 from 1.26.5 to 1.26.18

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>

requirements.bazel.txt

@@ -5,7 +5,7 @@ protobuf>=3.5.0.post1, < 4.0dev
 wheel==0.38.1
 oauth2client==4.1.0
 requests==2.25.1
-urllib3==1.26.5
+urllib3==1.26.18
 chardet==3.0.4
 certifi==2023.7.22
 idna==2.7