message: chore: speed up nvm installation on Travis CI
  You don't need to have the whole commit history of `nvm`, let's speed up the clone process.
diff: @@ -23,7 +23,7 @@ os:
  before_install:
  - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then
  rm -rf ~/.nvm;
  - git clone https://github.com/creationix/nvm.git ~/.nvm;
  + git clone --depth 1 https://github.com/creationix/nvm.git ~/.nvm;
  source ~/.nvm/nvm.sh;
  nvm --version;
  nvm install $NODE_VERSION;
  