If you want to test the vuetify development branch in your project, you might think you could use the github URL to the dev branch of the repository, like this:
yarn add git://github.com/vuetifyjs/vuetify#dev
However, this does not work. The files in dist/* are not rebuilt after every commit- you're probably just importing the most recent release.
(Using 'yarn' here as package manager- npm will be similar).
First, clone the development branch from github. Then register it with 'yarn link'. Finally use the linked version in your project.
git clone -b dev https://github.com/vuetifyjs/vuetify.git
cd vuetify
yarn
yarn run build
yarn link
cd ...../your-project
yarn link vuetify
yarn
Since you have locally built files in your copy of the repo, it's probably best to reset the repo before update & rebuild:
cd vuetify
git reset --hard
git pull
yarn run build