Bump pytest-cov from 2.12.1 to 3.0.0

Bumps [pytest-cov](https://github.com/pytest-dev/pytest-cov) from 2.12.1 to 3.0.0.
- [Release notes](https://github.com/pytest-dev/pytest-cov/releases)
- [Changelog](https://github.com/pytest-dev/pytest-cov/blob/master/CHANGELOG.rst)
- [Commits](pytest-dev/pytest-cov@v2.12.1...v3.0.0)

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

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

Author: dependabot[bot]

test-requirements.txt

@@ -18,7 +18,7 @@ charset-normalizer==2.0.1
     # via requests
 contextlib2==21.6.0
     # via -r test-requirements.in
-coverage==6.1.1
+coverage[toml]==6.1.1
     # via pytest-cov
 cssselect==1.1.0
     # via -r test-requirements.in
@@ -52,7 +52,7 @@ pytest==6.2.5
     # via
     #   -r test-requirements.in
     #   pytest-cov
-pytest-cov==2.12.1
+pytest-cov==3.0.0
     # via -r test-requirements.in
 pytz==2021.3
     # via babel
@@ -75,8 +75,8 @@ sphinxcontrib-qthelp==1.0.3
 sphinxcontrib-serializinghtml==1.1.5
     # via sphinx
 toml==0.10.2
-    # via
-    #   pytest
-    #   pytest-cov
+    # via pytest
+tomli==1.2.2
+    # via coverage
 urllib3==1.26.7
     # via requests