fix(landing): Udate contact button to lui primary style as the lui te…

…rtiary style changed. (#2546)

* Roll back  the contact up button style as the lui button tertiary style changed.

* Deprecatee tertiary button style.

* Update to className

* Update the lui primary button.

packages/landing/src/components/layout.header.tsx

@@ -70,7 +70,7 @@ export class Header extends Component<unknown, HeaderState> {
 
           <h6>Developer API Keys</h6>
           <p>Contact us for free API keys with better support for public web and mobile apps.</p>
-          <button className="lui-button lui-button-tertiary contact-us" onClick={this.contactUs}>
+          <button className="lui-button lui-button-primary contact-us" onClick={this.contactUs}>
             Contact us
           </button>