Log Message:
py-yaml: updated to 5.1

5.1:
* Some modernization of the test running
* Install tox in a virtualenv
* Allow colon in a plain scalar in a flow context
* Fix typos
* Improve RepresenterError creation
* Resolves 57, update readme issues link
* Document and test Python 3.6 support
* Use Travis CI built in pip cache support
* Remove tox workaround for Travis CI
* Adding support to Unicode characters over codepoint 0xffff
* Support unicode literals over codepoint 0xffff
* add 3.12 changelog
* Fallback to Pure Python if Compilation fails
* Drop unsupported Python 3.3
* Include license file in the generated wheel package
* Removed Python 2.6 & 3.3 support
* Remove commented out Psyco code
* Remove call to ord in lib3 emitter code
* Allow to turn off sorting keys in Dumper
* Test on Python 3.7-dev
* Support escaped slash in double quotes "\/"
* Import Hashable from collections.abc
* Make default_flow_style=False
* Deprecate yaml.load and add FullLoader and UnsafeLoader classes
* Windows Appveyor build