Update to Lit 2.0.0 (manually)

Will attempt to get this back to syncing with monorepo history per https://github.com/lit/lit#exporting-starter-templates in a follow-up.

src/my-element.ts

@@ -10,12 +10,13 @@ import {customElement, property} from 'lit/decorators.js';
 /**
  * An example element.
  *
+ * @fires count-changed - Indicates when the count changes
  * @slot - This element has a slot
  * @csspart button - The button
  */
 @customElement('my-element')
 export class MyElement extends LitElement {
-  static styles = css`
+  static override styles = css`
     :host {
       display: block;
       border: solid 1px gray;
@@ -36,9 +37,9 @@ export class MyElement extends LitElement {
   @property({type: Number})
   count = 0;
 
-  render() {
+  override render() {
     return html`
-      <h1>Hello, ${this.name}!</h1>
+      <h1>${this.sayHello(this.name)}!</h1>
       <button @click=${this._onClick} part="button">
         Click Count: ${this.count}
       </button>
@@ -48,10 +49,15 @@ export class MyElement extends LitElement {
 
   private _onClick() {
     this.count++;
+    this.dispatchEvent(new CustomEvent('count-changed'));
   }
 
-  foo(): string {
-    return 'foo';
+  /**
+   * Formats a greeting
+   * @param name The name to say "Hello" to
+   */
+  sayHello(name: string): string {
+    return `Hello, ${name}`;
   }
 }
 

src/test/my-element_test.ts

@@ -6,9 +6,8 @@
 
 import {MyElement} from '../my-element.js';
 
-import {fixture, html} from '@open-wc/testing';
-
-const assert = chai.assert;
+import {fixture, assert} from '@open-wc/testing';
+import {html} from 'lit/static-html.js';
 
 suite('my-element', () => {
   test('is defined', () => {