Bump urllib3 from 1.26.4 to 1.26.6

Bumps [urllib3](https://github.com/urllib3/urllib3) from 1.26.4 to 1.26.6.
- [Release notes](https://github.com/urllib3/urllib3/releases)
- [Changelog](https://github.com/urllib3/urllib3/blob/1.26.6/CHANGES.rst)
- [Commits](urllib3/urllib3@1.26.4...1.26.6)

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

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

Author: dependabot[bot]

docs-requirements.txt

@@ -48,5 +48,5 @@ sphinxcontrib-qthelp==1.0.3
     # via sphinx
 sphinxcontrib-serializinghtml==1.1.4
     # via sphinx
-urllib3==1.26.4
+urllib3==1.26.6
     # via requests

test-requirements.txt

@@ -48,12 +48,12 @@ pygments==2.8.1
     # via sphinx
 pyparsing==2.4.7
     # via packaging
-pytest-cov==2.11.1
-    # via -r test-requirements.in
 pytest==6.2.3
     # via
     #   -r test-requirements.in
     #   pytest-cov
+pytest-cov==2.11.1
+    # via -r test-requirements.in
 pytz==2021.1
     # via babel
 requests==2.25.1
@@ -76,5 +76,5 @@ sphinxcontrib-serializinghtml==1.1.4
     # via sphinx
 toml==0.10.2
     # via pytest
-urllib3==1.26.4
+urllib3==1.26.6
     # via requests