Scope npm package

[nventuro]

This changes the package from openzeppelin-test-helpers to @openzeppelin/test-helpers. Once 0.5.0 is published under this new name, we should deprecate the old package. I'm not sure yet if we should also publish 0.5.0 with the old name.

[frangio]

We shouldn't deprecate all of the existing versions of openzeppelin-test-helpers because that would be very annoying for people using 0.4 who don't want to upgrade. We should publish at least 0.5.0 and then deprecate that version, so that once people upgrade they receive the recommendation to migrate.

[nventuro]

Ah, I thought deprecations were package-wide. That makes a lot of sense, thanks!

[frangio]

I found some things that still need changing.

openzeppelin-test-helpers/scripts/release/release.sh

Line 60 in b5e269e

npm dist-tag rm --otp "$(prompt_otp)" openzeppelin-test-helpers next

openzeppelin-test-helpers/src/expectRevert.js

Line 43 in b5e269e

console.log(`${colors.white.bgBlack('openzeppelin-test-helpers')} ${colors.black.bgYellow('WARN')} \

[frangio]

LGTM, but please add a note in the Changelog.

What do you think about holding off on merging this until we actually release 0.5.0? So that we don't have to juggle to release openzeppelin-test-helpers@0.5.0.