Return list of strings instead of just string as dictionary values

[efe]

[yigitguler]

I think this update is backward-compatible, right?

[efe]

@yigitguler It isn't. Because some of the existing error messages (raising string) will behave differently. Should we bump the version to 0.2.1?

[yigitguler]

But FE guys are can handle a list of errors, right? I think that's an important point. AFAIK they handle this, but it will be wise to make a version bump. Also what is preventing us to make this 1.0 ? We are already using this package for years in production :)

[alicertel]

I think this update is backward-compatible, right?

Technically this is a bug fix. FE should always expect list of errors for a key according to our documentation. But if some of the client handled a specific key as a string without telling us this might break something.

Version 1.0.0 sounds nice.