Bump contextlib2 from 0.6.0.post1 to 21.6.0

Bumps [contextlib2](https://github.com/jazzband/contextlib2) from 0.6.0.post1 to 21.6.0.
- [Release notes](https://github.com/jazzband/contextlib2/releases)
- [Changelog](https://github.com/jazzband/contextlib2/blob/master/NEWS.rst)
- [Commits](jazzband/contextlib2@v0.6.0.post1...21.6.0)

---
updated-dependencies:
- dependency-name: contextlib2
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

test-requirements.txt

@@ -16,7 +16,7 @@ certifi==2020.12.5
     # via requests
 chardet==4.0.0
     # via requests
-contextlib2==0.6.0.post1
+contextlib2==21.6.0
     # via -r test-requirements.in
 coverage==5.5
     # via pytest-cov
@@ -44,7 +44,7 @@ pluggy==0.13.1
     # via pytest
 py==1.10.0
     # via pytest
-pygments==2.8.1
+pygments==2.9.0
     # via sphinx
 pyparsing==2.4.7
     # via packaging
@@ -72,7 +72,7 @@ sphinxcontrib-jsmath==1.0.1
     # via sphinx
 sphinxcontrib-qthelp==1.0.3
     # via sphinx
-sphinxcontrib-serializinghtml==1.1.4
+sphinxcontrib-serializinghtml==1.1.5
     # via sphinx
 toml==0.10.2
     # via pytest