build(deps): bump urllib3 from 1.26.14 to 1.26.15

Bumps [urllib3](https://github.com/urllib3/urllib3) from 1.26.14 to 1.26.15.
- [Release notes](https://github.com/urllib3/urllib3/releases)
- [Changelog](https://github.com/urllib3/urllib3/blob/main/CHANGES.rst)
- [Commits](urllib3/urllib3@1.26.14...1.26.15)

---
updated-dependencies:
- dependency-name: urllib3
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

requirements/pinned.txt

@@ -7,4 +7,4 @@ pycparser==2.21           # via cffi
 pynacl==1.5.0             # via securesystemslib
 requests==2.28.2
 securesystemslib[crypto,pynacl]==0.26.0
-urllib3==1.26.14           # via requests
+urllib3==1.26.15           # via requests