0.3.0: asterisks should only be stripped from the left

[Ewen Le Bihan]

If a changelog entry ends with italics, eg:

### Changed

- Lorem ipsum dolor sit *amet*

Then the parsed entry would be:

"changed": [
    "Lorem ipsum dolor sit *amet"
]

Which seems invalid to me.

A one-character change in _changelog.py fixes this problem:

- line.strip(" -*")
+ line.lstrip(" -*")

I can do a PR too, but since this change is so quick, It'll be easier if @Colin-b can do it.

[Colin Bounouar]

Release 0.3.1 is now available in pypi