Bump cached-property from 1.4.3 to 1.5.1

Bumps [cached-property](https://github.com/pydanny/cached-property) from 1.4.3 to 1.5.1.
- [Release notes](https://github.com/pydanny/cached-property/releases)
- [Changelog](https://github.com/pydanny/cached-property/blob/master/HISTORY.rst)
- [Commits](pydanny/cached-property@1.4.3...1.5.1)

Signed-off-by: dependabot[bot] <support@dependabot.com>

Author: dependabot-support

requirements/constraints.txt

@@ -5,7 +5,7 @@ aiomysql==0.0.19
 asn1crypto==0.24.0
 aspy.yaml==1.1.1
 async-timeout==3.0.1
-cached-property==1.4.3
+cached-property==1.5.1
 cffi==1.11.5
 chardet==3.0.4
 colorama==0.3.9