Bump cvxpy from 1.1.14 to 1.1.15 (AtsushiSakai#536)

Bumps [cvxpy](https://github.com/cvxgrp/cvxpy) from 1.1.14 to 1.1.15.
- [Release notes](https://github.com/cvxgrp/cvxpy/releases)
- [Changelog](https://github.com/cvxpy/cvxpy/blob/master/CHANGELOG.md)
- [Commits](cvxgrp/cvxpy@v1.1.14...v1.1.15)

---
updated-dependencies:
- dependency-name: cvxpy
  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

@@ -2,4 +2,4 @@ numpy == 1.21.1
 scipy == 1.7.1
 pandas == 1.3.1
 matplotlib == 3.4.2
-cvxpy == 1.1.14
+cvxpy == 1.1.15