Switch from npm update to npm install

npm update doesn't do what you think it does: It updates all internal
dependencies of each package, as a maintainer would do when testing new
versions to update their `package.json`; it doesn't refresh just the
specified package, but the things within it.

`npm install` actually does the right thing, upgrading to the `@latest`
tagged version of the package.
Merge pull request #223 from aredridel/npm-install-i-dont-think-that-word-means-what-you-think-it-means

Switch from npm update to npm install.