Bump scipy from 1.5.4 to 1.6.0 (AtsushiSakai#454)

Bumps [scipy](https://github.com/scipy/scipy) from 1.5.4 to 1.6.0.
- [Release notes](https://github.com/scipy/scipy/releases)
- [Commits](scipy/scipy@v1.5.4...v1.6.0)

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

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

Author: dependabot[bot]

requirements.txt

@@ -1,5 +1,5 @@
 numpy == 1.19.4
-scipy == 1.5.4
+scipy == 1.6.0
 pandas == 1.2.0
 matplotlib == 3.3.3
 cvxpy == 1.1.7