fix(trigger): replace yarn publish with npm publish

[eunjae-lee]

This PR replaces yarn publish with npm publish even if user is using yarn.

yarn publish uses yarn pack under the hood, and there is a critical bug in yarn pack.

Replacing yarn publish with npm publish requires an extra job, which is to set registry to the one of npm. Even though Ship.js calls npm publish, if it's triggered by yarn shipjs trigger, then yarn overrides the registry. It's coming from ~/.yarnrc. To revert this back, we need to prepend npm_config_registry=https://registry.npmjs.org/ to set the registry correctly.

[Haroenv]

you could set the registry in the yarnrc too, although I'm not sure how that works when shipjs is in node_modules

[eunjae-lee]

@Haroenv didn't see you comment here. You're right. That env var didn't work and now I'm trying again with yarn config set registry ...