Revert "Downgrade react to latest 15.x.x. (#4337)"
Revert "Downgrade react to latest 15.x.x. (#4337)"

This reverts commit b9104f16a2cac38c5b203198070e94676f577272.

mozilla-services/pageshot,mozilla-services/screenshots,mozilla-services/screenshots,mozilla-services/screenshots,mozilla-services/screenshots,mozilla-services/pageshot,mozilla-services/pageshot,mozilla-services/pageshot