chore(azure): node v4 compatible yarn (#5766)
chore(azure): node v4 compatible yarn (#5766)

Workaround for yarnpkg/yarn#6900
existentialism/prettier,rattrayalex/prettier,prettier/prettier,existentialism/prettier,prettier/prettier,prettier/prettier,jlongster/prettier,rattrayalex/prettier,existentialism/prettier,prettier/prettier,rattrayalex/prettier,existentialism/prettier