Change to content hash for RN canary VERSION strings

[kassens]

With this change, the different files in RN will have different hashes. This replaces the git hash and means that the file content (including version) is only updated when the rest of the file content actually changes. This should remove "noop" changes that need to be synced that only update the version string.

A difference to the www implementation here is (and I'd be looking at updating www as well if this lands well) that each file has an individual hash instead of a combined content hash. This further reduces the number of updated files and I couldn't find a reason we need to have these in sync. The best I can gather is that this hash is used so folks don't directly compare version string and make future updates harder.

[react-sizebot]

Comparing: 9c75cd5...175a079

Critical size changes

Includes critical production bundles, as well as any change greater than 2%:

Name	+/-	Base	Current	+/- gzip	Base gzip	Current gzip
oss-stable/react-dom/cjs/react-dom.production.min.js	=	176.83 kB	176.83 kB	=	54.91 kB	54.91 kB
oss-experimental/react-dom/cjs/react-dom.production.min.js	=	173.26 kB	173.26 kB	=	54.04 kB	54.04 kB
facebook-www/ReactDOM-prod.classic.js	=	594.27 kB	594.27 kB	=	104.44 kB	104.44 kB
facebook-www/ReactDOM-prod.modern.js	=	577.53 kB	577.53 kB	=	101.47 kB	101.47 kB
test_utils/ReactAllWarnings.js	Deleted	66.63 kB	0.00 kB	Deleted	16.28 kB	0.00 kB

Significant size changes

Includes any change greater than 0.2%:

Expand to show

Name	+/-	Base	Current	+/- gzip	Base gzip	Current gzip
test_utils/ReactAllWarnings.js	Deleted	66.63 kB	0.00 kB	Deleted	16.28 kB	0.00 kB

Generated by 🚫 dangerJS against 175a079

[josephsavona]

This seems fine if it's only updating files that are synced to Meta, rather than files used in OSS. Hard to tell from the code if that's strictly the case.

[rickhanlonii]

LGTM, let's just follow up to confirm it doesn't impact the OSS files