upgrade to react 16.3

[meg2208]

Closes #1427 and will be useful for a few other issues.

➜  popcode git:(react-16.3) ✗ yarn list react                      
yarn list v0.27.5
└─ react@16.3.2

[outoftime]

@meg2208 should #1402 be included in this?

[meg2208]

This version is definitely compatible with those lifecycle methods, so I would say no need, but #1402 should be considered a pretty high priority since we are going to want to upgrade to 16.4 if we start using StrictMode. According to this in this version it will only throw a deprecation warning when you turn on StrictMode or AsyncMode in 16.3. Looks like #1402 is definitely a strict requirement for 16.4, but that is not out yet.

[meg2208]

@outoftime I would like to merge this asap so I can use AsyncMode for #1426 and we wouldn't have to add any dependencies for the async rendering.

[outoftime]

@meg2208 OK, yeah from looking at the changelog/article I share your conclusion that 16.3 itself does not introduce any new deprecations, so I’m down to merge this on the merits.

However, I’m not sure that this should immediately change the picture for #1426, for a couple reasons:

• As far as I can tell, AsyncMode is still an unstable API in 16.3—generally I think we should prefer a stable third-party library to an unstable built-in, and then make the switch when the built-in becomes stable.
• From a VERY cursory glance, I’m not sure that AsyncMode is what we want anyway—I think that concerns asynchronous prop updates as a performance optimization, rather than rendering a component contingent on the outcome of an asynchronous operation (i.e. a Promise). I could definitely be wrong about this though.

Anywho, I still see no reason not to go ahead and upgrade, so I’m gonna merge this!