message: config(travis): pin yarn to v1
  v2 contains breaking changes
diff: @@ -15,7 +15,7 @@ node_js:
  env:
  - YARN_GPG=no
  -# Travis uses inconsistent yarn versions across platforms. force latest.
  +# Travis uses inconsistent yarn versions across platforms.
  before_install:
  - - curl -o- -L https://yarnpkg.com/install.sh | bash -s
  + - curl -o- -L https://yarnpkg.com/install.sh | bash -s -- --version 1.22.0
  - export PATH=$HOME/.yarn/bin:$PATH
  