revert coveralls to use v2

Author: scottheng96

.github/workflows/ci.yml

@@ -47,7 +47,7 @@ jobs:
       - run: npm run test-ci
         env:
           NODE_OPTIONS: '--max-old-space-size=8192'
-      - name: Submit test coverage to Coveralls-next
-        run: cat coverage/lcov.info | npx coveralls-next
+      - name: Submit coverage to Coveralls
+        uses: coverallsapp/github-action@v2
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}