Summary:npm-publish.js is not cohesive enough: besides building and publishing it also modifies some files.
It is better to have a separate script that will bump versions, make a commit and tag it.
scripts/bump-oss-version.js does exactly that.
This simplifies release process and allows manual release to npm if CI is not available.
Closes https://github.com/facebook/react-native/pull/6625
Differential Revision: D3092849
fb-gh-sync-id: 92cf38bd3df31c8c9c433fc5f9e15c129855fe0e
shipit-source-id: 92cf38bd3df31c8c9c433fc5f9e15c129855fe0e