Bump py from 1.5.2 to 1.10.0 in /assignments

Bumps [py](https://github.com/pytest-dev/py) from 1.5.2 to 1.10.0.
- [Release notes](https://github.com/pytest-dev/py/releases)
- [Changelog](https://github.com/pytest-dev/py/blob/master/CHANGELOG.rst)
- [Commits](pytest-dev/py@1.5.2...1.10.0)

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

Author: dependabot[bot]

assignments/requirements.txt

@@ -1,5 +1,5 @@
 attrs==17.4.0
 pluggy==0.6.0
-py==1.5.2
+py==1.10.0
 pytest==3.4.0
 six==1.11.0