peer dependencies and versions

[guillaumearm]

I think we have to discuss about redux-polyglot peer dependencies.

In #91, @satazor asked why prop-types should be a peer dep, This is a very good question and we should think about it.

There are some points to cover :

• Which dependencies should be peer
• Which versions of this dependencies works together ?
• Which versions of this dependencies works with redux-polyglot ?

In addition, it's can be a very good idea to test this, for example :

• run redux-polyglot unit test suites with react@15, react@14 and so on.

Refs :

• https://nodejs.org/en/blog/npm/peer-dependencies/
• https://stackoverflow.com/questions/26737819/why-use-peer-dependencies-in-npm-for-plugins?utm_medium=organic&utm_source=google_rich_qa&utm_campaign=google_rich_qa