## Types of changes
<!--- What types of changes does your code introduce? Put an `x` in all the boxes that apply: -->
- [ ] Bug fix (a non-breaking change which fixes an issue)
- [x] New feature (a non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing functionality to change)
## Description
Resolves#3920 by adding a warning during the build process and a small disclaimer into the default page component.
## Checklist:
- [ ] My change requires a change to the documentation.
- [ ] I have updated the documentation accordingly. (PR: #)
- [x] I have added tests to cover my changes (if not applicable, please state why)
- [x] All new and existing tests are passing.
* fix: appveyor test failure
* ci: bring back yarn cache
* ci: turn off matrix
* refactor: use babel instead of esm in jest
* refactor: use es modules in fixtures
