docs: add vercel to docsite footer

docs/src/components/Footer.svelte

@@ -0,0 +1,24 @@
+<script>
+  import { Content, Grid, Row, Column, Link } from "carbon-components-svelte";
+</script>
+
+<style>
+  footer {
+    background: var(--cds-ui-01);
+  }
+</style>
+
+<footer class="bx--content">
+  <Grid>
+    <Row>
+      <Column>
+        <Link
+          href="https://www.vercel.com?utm_source=carbon-components-svelte&utm_campaign=oss"
+          target="_blank"
+        >
+          <img src="/powered-by-vercel.svg" alt="Deploys by Vercel" />
+        </Link>
+      </Column>
+    </Row>
+  </Grid>
+</footer>

docs/src/pages/_layout.svelte

@@ -20,6 +20,7 @@
   } from "carbon-components-svelte";
   import LogoGithub20 from "carbon-icons-svelte/lib/LogoGithub20";
   import Theme from "../components/Theme.svelte";
+  import Footer from "../components/Footer.svelte";
 
   let isOpen = false;
   let isSideNavOpen = true;
@@ -238,4 +239,5 @@
     </SideNavItems>
   </SideNav>
   <slot />
+  <Footer />
 </Theme>