First minor bump for PSR compliance

I've modified the code so now it makes use of PSR 7 request and response interfaces and PSR 18 client interfaces.

This is a first minor bump as we're still backwards compatible without any known breaks, but now completely ready for the future to facilitate any HTTP client interface that implements PSR 18.

Enjoy the improvements.

Release v0.0.6

We've updated the package to include:

• Typo fix in the README document (PR #6 by @abiodunsulaiman694)
• Allowing custom options into the HTTP client (PR #7 by @srsbiz)
• Testing against PHP 7.3
• Improving mutation tests on CircleCI

Also read my blog article A word about my Have I Been Pwned package where I explain how this password lookup works behind the scenes and to ensure the audience that no passwords are shared over the wire.