Bump matplotlib from 3.5.0 to 3.5.1 (AtsushiSakai#599)

Bumps [matplotlib](https://github.com/matplotlib/matplotlib) from 3.5.0 to 3.5.1.
- [Release notes](https://github.com/matplotlib/matplotlib/releases)
- [Commits](matplotlib/matplotlib@v3.5.0...v3.5.1)

---
updated-dependencies:
- dependency-name: matplotlib
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

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

Author: dependabot[bot]

requirements.txt

@@ -1,7 +1,7 @@
 numpy == 1.21.4
 scipy == 1.7.3
 pandas == 1.3.5
-matplotlib == 3.5.0
+matplotlib == 3.5.1
 cvxpy == 1.1.17
 pytest == 6.2.5 # For unit test
 pytest-xdist == 2.5.0 # For unit test