insert_license - write file back in original encoding

[mdeweerd]

In insert_license.py we can red:

    for encoding in ('utf8', 'ISO-8859-1'):  # we could use the chardet library to support more encodings

But when writeing the file back, utf8 is used, so the original file encoding could be changed.

It would be better to remember the original encoding to reuse it on writeback.

[Lucas-C]

Agreed, that would be better.

Have you faced a case where the wrong encoding was used on writeback?
I guess this line makes it very likely to happen:
https://github.com/Lucas-C/pre-commit-hooks/blob/v1.2.0/pre_commit_hooks/insert_license.py#L233

[mdeweerd]

Yes, I was faced with that.

[Lucas-C]

I submitted #44 in order to implement this