remove unnecessary step for CI

.github/workflows/ci.yml

@@ -215,13 +215,6 @@ jobs:
         yarn server:ci
       env:
         MONGO_URI: mongodb://localhost:${{ job.services.mongodb.ports['27017'] }}/growi-${{ steps.getdbname.outputs.suffix }}
-    - name: yarn server:ci with MongoDB 3.6
-      working-directory: ./packages/app
-      run: |
-        cp config/ci/.env.local.for-ci .env.production.local
-        yarn server:ci
-      env:
-        MONGO_URI: mongodb://localhost:${{ job.services.mongodb36.ports['27017'] }}/growi-${{ steps.getdbname.outputs.suffix }}
 
     - name: Upload report as artifact
       uses: actions/upload-artifact@v2