Update @polymer/lit-element to lit-element

package.json

@@ -20,9 +20,9 @@
   },
   "dependencies": {
     "@polymer/app-layout": "^3.0.0",
-    "@polymer/lit-element": "^0.7.0",
     "@polymer/polymer": "^3.1.0",
     "@webcomponents/webcomponentsjs": "^2.0.0",
+    "lit-element": "^2.0.0-rc.1",
     "pwa-helpers": "^0.9.0",
     "redux": "^4.0.0",
     "redux-thunk": "^2.3.0",

src/components/button-shared-styles.js

@@ -8,7 +8,7 @@ Code distributed by Google as part of the polymer project is also
 subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 */
 
-import { css } from '@polymer/lit-element';
+import { css } from 'lit-element';
 
 export const ButtonSharedStyles = css`
   button {

src/components/counter-element.js

@@ -8,7 +8,7 @@ Code distributed by Google as part of the polymer project is also
 subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 */
 
-import { LitElement, html, css } from '@polymer/lit-element';
+import { LitElement, html, css } from 'lit-element';
 
 // These are the elements needed by this element.
 import { plusIcon, minusIcon } from './my-icons.js';

src/components/my-app.js

@@ -8,7 +8,7 @@ Code distributed by Google as part of the polymer project is also
 subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 */
 
-import { LitElement, html, css } from '@polymer/lit-element';
+import { LitElement, html, css } from 'lit-element';
 import { setPassiveTouchGestures } from '@polymer/polymer/lib/utils/settings.js';
 import { connect } from 'pwa-helpers/connect-mixin.js';
 import { installMediaQueryWatcher } from 'pwa-helpers/media-query.js';

src/components/my-view1.js

@@ -8,7 +8,7 @@ Code distributed by Google as part of the polymer project is also
 subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 */
 
-import { html } from '@polymer/lit-element';
+import { html } from 'lit-element';
 import { PageViewElement } from './page-view-element.js';
 
 // These are the shared styles needed by this element.

src/components/my-view2.js

@@ -8,7 +8,7 @@ Code distributed by Google as part of the polymer project is also
 subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 */
 
-import { html } from '@polymer/lit-element';
+import { html } from 'lit-element';
 import { PageViewElement } from './page-view-element.js';
 import { connect } from 'pwa-helpers/connect-mixin.js';
 

src/components/my-view3.js

@@ -8,7 +8,7 @@ Code distributed by Google as part of the polymer project is also
 subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 */
 
-import { html, css } from '@polymer/lit-element';
+import { html, css } from 'lit-element';
 import { PageViewElement } from './page-view-element.js';
 import { connect } from 'pwa-helpers/connect-mixin.js';
 

src/components/my-view404.js

@@ -8,7 +8,7 @@ Code distributed by Google as part of the polymer project is also
 subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 */
 
-import { html } from '@polymer/lit-element';
+import { html } from 'lit-element';
 import { PageViewElement } from './page-view-element.js';
 
 // These are the shared styles needed by this element.

src/components/page-view-element.js

@@ -8,7 +8,7 @@ Code distributed by Google as part of the polymer project is also
 subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 */
 
-import { LitElement } from '@polymer/lit-element';
+import { LitElement } from 'lit-element';
 
 export class PageViewElement extends LitElement {
   // Only render this page if it's actually visible.

src/components/shared-styles.js

@@ -8,7 +8,7 @@ Code distributed by Google as part of the polymer project is also
 subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 */
 
-import { css } from '@polymer/lit-element';
+import { css } from 'lit-element';
 
 export const SharedStyles = css`
   :host {

src/components/shop-cart.js

@@ -8,7 +8,7 @@ Code distributed by Google as part of the polymer project is also
 subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 */
 
-import { LitElement, html, css } from '@polymer/lit-element';
+import { LitElement, html, css } from 'lit-element';
 import { connect } from 'pwa-helpers/connect-mixin.js';
 
 // This element is connected to the Redux store.

src/components/shop-item.js

@@ -8,7 +8,7 @@ Code distributed by Google as part of the polymer project is also
 subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 */
 
-import { LitElement, html } from '@polymer/lit-element';
+import { LitElement, html } from 'lit-element';
 
 // This element is *not* connected to the Redux store.
 class ShopItem extends LitElement {

src/components/shop-products.js

@@ -8,7 +8,7 @@ Code distributed by Google as part of the polymer project is also
 subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 */
 
-import { LitElement, html, css } from '@polymer/lit-element';
+import { LitElement, html, css } from 'lit-element';
 import { connect } from 'pwa-helpers/connect-mixin.js';
 
 // This element is connected to the Redux store.

src/components/snack-bar.js

@@ -8,7 +8,7 @@ Code distributed by Google as part of the polymer project is also
 subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 */
 
-import { LitElement, html, css } from '@polymer/lit-element';
+import { LitElement, html, css } from 'lit-element';
 
 class SnackBar extends LitElement {
   static get properties() {