chore(deps): bump urllib3 from 1.26.14 to 1.26.18 in /test

Bumps [urllib3](https://github.com/urllib3/urllib3) from 1.26.14 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@1.26.14...1.26.18)

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

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

test/upstream-requirements-py311.txt

@@ -16,5 +16,5 @@ pytest-mock==3.6.1
 python-dateutil==2.8.2
 s3transfer==0.6.0
 six==1.16.0
-urllib3==1.26.14
+urllib3==1.26.18
 wrapt==1.14.1

test/upstream-requirements-py37.txt

@@ -20,6 +20,6 @@ s3transfer==0.6.0
 six==1.16.0
 tomli==2.0.1
 typing_extensions==4.4.0
-urllib3==1.26.14
+urllib3==1.26.18
 wrapt==1.14.1
 zipp==3.11.0