fix: run yarn

Author: jdx

.circleci/config.yml

@@ -20,6 +20,7 @@ jobs:
           command: |
             git clone "https://x-access-token:$(./scripts/github_token.js 290530)@github.com/heroku/typescript-api-schema.git" repo
             cd repo
+            yarn
             git config --global push.default simple
             git config --global user.name "$GIT_AUTHOR_NAME"
             git config --global user.email "$GIT_AUTHOR_EMAIL"