MAINT: Bump hypothesis from 5.5.4 to 5.6.0

Bumps [hypothesis](https://github.com/HypothesisWorks/hypothesis) from 5.5.4 to 5.6.0.
- [Release notes](https://github.com/HypothesisWorks/hypothesis/releases)
- [Commits](HypothesisWorks/hypothesis@hypothesis-python-5.5.4...hypothesis-python-5.6.0)

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

Author: dependabot-preview[bot]

test_requirements.txt

@@ -1,5 +1,5 @@
 cython==0.29.15
-hypothesis==5.5.4
+hypothesis==5.6.0
 pytest==5.3.5
 pytz==2019.3
 pytest-cov==2.8.1