chore(🐙): add build step for packages in CI workflow (#390)

Author: wcandillon

.github/workflows/ci.yml

@@ -49,6 +49,9 @@ jobs:
       - name: Typecheck files
         run: yarn tsc
 
+      - name: Build packages
+        run: yarn turbo run build --filter='./packages/*'
+
       # Build the docs site the same way the Pages deploy does (GITHUB_PAGES set,
       # so the project base path is applied) to catch broken links / build
       # regressions before they reach main.