Improve README

Full Changelog: v2.3.2...v2.3.3

v2.3.2

What's Changed

• add minified size and getting started section into README.md by @emanuelecaurio in #1

Full Changelog: v2.3.1...v2.3.2

v2.3.1

ChangeLog

add "preversion" and "postversion" into package.json

Full Changelog: https://github.com/emanuelecaurio/basic-react-router/commits/v2.3.1