Adds support for React 17

[uzikilon]

Adds React 17 to the peer dependencies as React 17 has no actual impact on this package

[mac-s-g]

beautiful. thank you.

[fgarcia]

Did this solve all dependency problems? I am still getting one walking down the dependency tree (after upgrading to npm 7)

npm ERR! Could not resolve dependency:
npm ERR! peer react@">=0.14.0 <17.0.0" from react-textarea-autosize@6.1.0
npm ERR! node_modules/react-json-view/node_modules/react-textarea-autosize
npm ERR!   react-textarea-autosize@"^6.1.0" from react-json-view@1.21.0
npm ERR!   node_modules/react-json-view
npm ERR!     dev react-json-view@"^1.21.0" from the root project