Bump urllib3 from 1.24.2 to 1.26.5 in /requirements

Bumps [urllib3](https://github.com/urllib3/urllib3) from 1.24.2 to 1.26.5.
- [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/1.24.2...1.26.5)

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

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

requirements/build.txt

@@ -31,5 +31,5 @@ python-jose-cryptodome==1.3.2
 git+https://github.com/mozilla/python_moztelemetry.git@v0.10.4#egg=python-moztelemetry
 python-snappy==0.5.3
 ujson==1.35
-urllib3==1.24.2
+urllib3==1.26.5
 requests==2.22.0