Make non-ascii character error in YAML parse more specific

[pablo-de-andres]

In GitLab by @pablo-de-andres on Mar 5, 2020, 13:40

Relates to #255. When PyYaml finds a non-ascii character, it raises a UnicodeDecodeError: 'charmap' codec can't decode byte 0xBB in position xxx

We should try to make the error more informative, maybe provide a position for the character if possible?

[pablo-de-andres]

In GitLab by @urbanmatthias on Mar 5, 2020, 13:41

We could also state in the error message, that this problem only occurs on windows