Use AndreMiras' version of Coveralls action

According to coverallsapp/github-action#4 (comment),
this version works, unlike the official https://github.com/marketplace/actions/coveralls-github-action.

.github/workflows/test.yml

@@ -33,7 +33,16 @@ jobs:
       run: |
         flake8 --select F401, F405,E231 quantecon
         nosetests --with-coverage -a "!slow" --cover-package=quantecon
-    - name: Coveralls
-      uses: coverallsapp/github-action@master
+    - name: Coveralls Parallel
+      uses: AndreMiras/coveralls-python-action@develop
       with:
-        github-token: ${{ secrets.github_token }}
+        flag-name: run-${{ matrix.test_number }}
+        parallel: true
+  coveralls_finish:
+    needs: test
+    runs-on: ubuntu-latest
+    steps:
+    - name: Coveralls Finished
+      uses: AndreMiras/coveralls-python-action@develop
+      with:
+        parallel-finished: true