[DNM] DRAFT - experimental - try strict mode React + Relay hooks

[kmjennison]

The ultimate goal of this exploration is to use Relay hooks. This should allow us to more easily use the Relay store correctly; for example, by returning Relay store data from useData, which currently suffers from rendering bugs for top-level pages when the Relay store changes.

If we want to use Relay hooks now, we need to rely on an unstable React Suspense and consequently make sure all code is compatible with React strict mode.

Some of the work this requires:

• Upgrade to Material UI v5, which should support strict mode
  • We may need to change our styling solution -- see comments in this PR
• Update Relay dependencies
• Enable React strict mode
• Install react@experimental and react-dom@experimental
• Enable concurrent React
• Use new Relay features
  • Test using a Relay hook for querying
  • Migrate containers, as needed
  • Migrate mutation logic, as needed

[vercel]

This pull request is being automatically deployed with Vercel (learn more).
To see the status of your deployment, click below or on the icon next to each commit.

🔍 Inspect: https://vercel.com/gladly-team/tab-web/4pFF9isXP6SHQmJHWwyMUTwiqyCE
✅ Preview: https://tab-web-git-kevin-fix-relay-data-gladly-team.vercel.app

[codecov]

Codecov Report

Merging #132 (189de55) into master (61876e0) will decrease coverage by 0.16%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##           master     #132      +/-   ##
==========================================
- Coverage   89.29%   89.13%   -0.17%     
==========================================
  Files          82       82              
  Lines        1149     1150       +1     
  Branches      268      266       -2     
==========================================
- Hits         1026     1025       -1     
- Misses        110      112       +2     
  Partials       13       13              

Impacted Files	Coverage Δ
src/components/ErrorPage.js	100.00% <ø> (ø)
src/pages/_document.js	0.00% <0.00%> (ø)
src/pages/account.js	100.00% <ø> (ø)
src/utils/hooks/useData.js	100.00% <ø> (ø)
src/utils/pageWrappers/withDataSSR.js	100.00% <ø> (ø)
src/components/Achievement.js	93.51% <100.00%> (-0.12%)	⬇️
src/pages/_app.js	92.85% <100.00%> (+0.26%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 61876e0...189de55. Read the comment docs.