build(deps): Bump urllib3 in /examples/knative/python/kn-py-vm-attr

Bumps [urllib3](https://github.com/urllib3/urllib3) from 1.26.18 to 1.26.19.
- [Release notes](https://github.com/urllib3/urllib3/releases)
- [Changelog](https://github.com/urllib3/urllib3/blob/main/CHANGES.rst)
- [Commits](urllib3/urllib3@1.26.18...1.26.19)

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

Signed-off-by: dependabot[bot] <[email protected]>

examples/knative/python/kn-py-vm-attr/requirements.txt

@@ -17,6 +17,6 @@ pyvmomi==7.0.2
     certifi==2024.7.4
     charset-normalizer==2.0.12
     idna==3.7
-    urllib3==1.26.18
+    urllib3==1.26.19
   six==1.16.0
 setuptools==65.5.1