Log Message:
py-yaml: updated to 6.0

6.0

Change README format to Markdown
Add a test for YAML 1.1 types
fix float resolver to ignore `.` and `._`
drop Python 2.7
Fix spelling of “hexadecimal”
fix representation of Enum subclasses
fix libyaml extension compiler warnings
fix ResourceWarning on leaked file descriptors
always require `Loader` arg to `yaml.load()`
remove remaining direct distutils usage