Remove button role for links with an href

[Chapabu]

Closes #388

I went to write some tests for this and noticed the TODO regarding moving to @testing-library/react, so I took the liberty of adding it and writing the tests using @testing-library/react as there weren't any for the component I edited.

I also tested it manually by adding a hrefBuilder prop in the demo, however this is not committed as I didn't want to alter the demo unnecessarily.

Lastly, I had to use promises as it was complaining about needed regenerator-runtime. In the interest of getting it done, I just returned the promise from the test rather than doing anything fancy.

[mattc-cogapp]

Lastly, I had to use promises as it was complaining about needed regenerator-runtime.

Sorry, I meant using promises rather than async/await.

[MonsieurV]

Perfect, thanks @mattc-cogapp!

I've done the setup to use async/await in tests.

Can you validate the build is working well for you? (I've changed Webpack version)

You can install the latest changes from master with:

npm install --save github:AdeleD/react-paginate#master

[Chapabu]

@MonsieurV Apologies for the delay with this - can confirm everything works fine :)