Ensure we add the correct version of react-dom

[tmeasday]

Issue: #1284

We need to use an equal version to the react version the app is using.

What I did

Looked in package.json#dependencies.

We could also look elsewhere (e.g. devDependencies), but that's where RN will put it.

How to test

cd /tmp
react-native init App
cd App
# ensure this is npm-linked
getstorybook
npm run storybook

@shilman maybe can test CRNA too?

[codecov]

Codecov Report

Merging #1349 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1349   +/-   ##
=======================================
  Coverage   13.76%   13.76%           
=======================================
  Files         202      202           
  Lines        4621     4621           
  Branches      598      507   -91     
=======================================
  Hits          636      636           
- Misses       3473     3552   +79     
+ Partials      512      433   -79

Impacted Files	Coverage Δ
addons/events/src/components/Event.js	0% <0%> (ø)	⬆️
addons/info/src/components/Node.js	0% <0%> (ø)	⬆️
addons/storyshots/src/storybook-channel-mock.js	0% <0%> (ø)	⬆️
app/react/src/client/preview/error_display.js	0% <0%> (ø)	⬆️
app/react/src/client/preview/reducer.js	0% <0%> (ø)	⬆️
lib/ui/src/modules/ui/configs/handle_routing.js	28.94% <0%> (ø)	⬆️
addons/knobs/src/components/PropField.js	10.86% <0%> (ø)	⬆️
app/react/src/client/preview/client_api.js	39.28% <0%> (ø)	⬆️
lib/ui/src/libs/key_events.js	23.25% <0%> (ø)	⬆️
lib/ui/src/modules/shortcuts/actions/shortcuts.js	6.25% <0%> (ø)	⬆️
... and 21 more

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[shilman]

LGTM! This is also where CRNA puts it.