Cannot decode output when exec is not found on Windows

[pawamoy]

Describe the bug
It seems CMD is not using UTF-8 by default. When a command fail (for example when an exec is not found, see #6), and failprint tries to decode the output, it fails.

To Reproduce
Same command as in #6.

Expected behavior
The error message is at least properly decoded and printed by failprint.

System (please complete the following information):

• failprint version: 0.4.1
• Python version: 3.6
• OS: Windows

Additional context
The encoding used by the console can be obtained with the command chcp. It prints a sentence in the current locale with, I hope always in this format, the "code page" at the end, something like Page de codes active : 850. This code page can then be used to decode the output. We could do something like this:

try:
    _, chcp_output = _run_process(["chcp"])
    os_encoding = re.search(r"(\d+)").group(1)  # code page does not lose characters
except UnicodeDecodeError:
    import locale  # locale sometimes lose characters (é -> ,)
    os_encoding = locale.getpreferredencoding()

try:
    stdout = stdout.decode("utf8")
except UnicodeDecodeError:
    if not os_encoding:
        raise
    stdout = stdout.decode(os_encoding)

[pawamoy]

Should be fixed in version 0.6.0.