Component demo doesn't work with lit-element because of lit-html

I created a component called [**`flickity-slider`**](https://www.webcomponents.org/element/flickity-slider). I tried to follow the demo for creating a demo for it, I got the demo to work locally, however, when I published the component my component was unable to do the following:

```js
import {LitElement, html} from '@polymer/lit-element';
```

I checked the network tab and the reason this line fails is because of the following imports that happen cause 404 network errors:

- _`lit-element`'s_ imports:
- https://npm-demos.appspot.com/@polymer/lib/updating-element.js?flickity-slider@1.0.7
- https://npm-demos.appspot.com/@polymer/lib/decorators.js?flickity-slider@1.0.7
- _`lit-html`'s_ imports:
- https://npm-demos.appspot.com/lib/default-template-processor.js?flickity-slider@1.0.7
- https://npm-demos.appspot.com/lib/template-result.js?flickity-slider@1.0.7
- https://npm-demos.appspot.com/lib/template.js?flickity-slider@1.0.7
- https://npm-demos.appspot.com/lib/template-instance.js?flickity-slider@1.0.7
- https://npm-demos.appspot.com/lib/part.js?flickity-slider@1.0.7
- https://npm-demos.appspot.com/lib/parts.js?flickity-slider@1.0.7
- https://npm-demos.appspot.com/lib/dom.js?flickity-slider@1.0.7
- https://npm-demos.appspot.com/lib/directive.js?flickity-slider@1.0.7
- https://npm-demos.appspot.com/lib/render.js?flickity-slider@1.0.7
- https://npm-demos.appspot.com/lib/template-factory.js?flickity-slider@1.0.7

[Link to demo](https://www.webcomponents.org/element/flickity-slider/demo/demo/index.html)

I'm assuming this is an issue affecting all `lit-element` projects, however, I couldn't find any information on this issue so I'm not 100% sure if `lit-element` demos are supported yet.