chore(ci): fix deploy-docs CI job

One step in the `deploy-docs` CI job contains a typo that causes it to
fail: `yarn -cwd ...` instead of `yarn --cwd ...`
This has been broken since a0488b3, but
has not been noticed because the job was not running. #17060 configured
the job to run as necessary, which brought up the error.

Example failure:
  - On v1.8.x:
    https://app.circleci.com/pipelines/github/angular/angular.js/
    153/workflows/6a9826ac-d191-4042-8c39-0c969c81e381/jobs/1606

This commit fixes the typo in the command.

.circleci/config.yml

@@ -387,7 +387,7 @@ jobs:
       - skip_unless_stable_branch
         # Install dependencies for Firebase functions to prevent parsing errors during deployment
         # See https://github.com/angular/angular.js/pull/16453
-      - run: yarn -cwd ~/ng/scripts/docs.angularjs.org-firebase/functions
+      - run: yarn --cwd scripts/docs.angularjs.org-firebase/functions
       - run: yarn firebase deploy --token "$FIREBASE_TOKEN" --only hosting
 
 workflows: