build(deps): update urllib3 requirement from >=1.26.11 to >=1.26.20

Updates the requirements on [urllib3](https://github.com/urllib3/urllib3) to permit the latest version.
- [Release notes](https://github.com/urllib3/urllib3/releases)
- [Changelog](https://github.com/urllib3/urllib3/blob/main/CHANGES.rst)
- [Commits](urllib3/urllib3@1.26.11...1.26.20)

---
updated-dependencies:
- dependency-name: urllib3
  dependency-version: 1.26.20
  dependency-type: direct:production
...

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

Author: dependabot[bot]

pyproject.toml

@@ -44,7 +44,7 @@ typing = [
     "mypy",
     # =================
     # TODO: remove redundant urllib3 and certifi after proper migration from setup.py
-    "urllib3>=1.26.11",
+    "urllib3>=1.26.20",
     "certifi",
     # =================
     "types-protobuf",