Bump pytest from 6.2.5 to 7.0.0 in /requirements (AtsushiSakai#640)

Bumps [pytest](https://github.com/pytest-dev/pytest) from 6.2.5 to 7.0.0.
- [Release notes](https://github.com/pytest-dev/pytest/releases)
- [Changelog](https://github.com/pytest-dev/pytest/blob/main/CHANGELOG.rst)
- [Commits](pytest-dev/pytest@6.2.5...7.0.0)

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

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

requirements/requirements.txt

@@ -3,7 +3,7 @@ scipy == 1.7.3
 pandas == 1.4.0
 matplotlib == 3.5.1
 cvxpy == 1.1.18
-pytest == 6.2.5 # For unit test
+pytest == 7.0.0 # For unit test
 pytest-xdist == 2.5.0 # For unit test
 mypy == 0.931 # For unit test
 flake8 == 4.0.1 # For unit test