To install you need first to create .npmrc file with @alttiri:registry=https://npm.pkg.github.com content:

echo @alttiri:registry=https://npm.pkg.github.com >> .npmrc

only then run

npm install @alttiri/util-node-js

Note, that GitHub Packages requires to have also ~/.npmrc file (.npmrc in your home dir) with //npm.pkg.github.com/:_authToken=TOKEN content, where TOKEN is a token with the read:packages permission, take it here https://github.com/settings/tokens/new.