[RFR] Relax react router dependency to avoid version mismatch

[fzaninotto]

Closes #3138

[fzaninotto]

The warnings come from history, which is a dependency of react-router-dom. history is resolved to the latest version (4.9.0) on new projects. It complains that react-router-dom uses an outdated way of calling the history adapters. The fix consists of relaxing the react-router-dom version constraint, to have a more recent version that calls history adapters the right way.