react-datepicker is missing peer dependencies

[pjonsson]

Looking at https://npmgraph.js.org/?q=https%3A%2F%2Fgithub.com%2FTerriaJS%2Fterriajs%2Fblob%2Fmain%2Fpackage.json, the "Graph" tab to the right has a header "Missing peer dependencies (2)" where [email protected] is listed as wanting react@^0.14.0 || ^15.0.0 and react-dom@^0.14.0 || ^15.0.0, so I'm guessing this version does not support the React version used by TerriaJS?

The react-datepicker package is also causing the warning of react-popper and popper.js under the "Deprecated modules" header.

[zoran995]

It will upgraded as part of the react upgrade or as a follow-up; we have most of it completed, but we need to sort out other things and currently open PRs before creating a bunch of PRs for it to avoid constant merge conflicts