Adding nodejs/releasers as maintainers #628

Refs: nodejs/Release#557

Any objections to adding the release team (@nodejs/releasers) as maintainers of https://github.com/nodejs/node-core-utils? The rationale is to give the release team the ability to maintain release process related tooling, git node release in this case.