Revert "Merge pull request #1295 from flutter-form-builder-ecosystem/dependabot/github_actions/codecov/codecov-action-4"

This reverts commit 272196f, reversing
changes made to c55499e.

Author: deandreamatias

.github/workflows/base.yaml

@@ -43,7 +43,7 @@ jobs:
       - name: Run tests
         run: flutter test --coverage
       - name: Upload coverage to Codecov
-        uses: codecov/codecov-action@v4
+        uses: codecov/codecov-action@v3
         with:
           files: coverage/lcov.info
           name: flutter_form_builder