refact: extra footer into its own component

src/components/Footer/index.tsx

@@ -0,0 +1,17 @@
+import React from "react"
+import * as SC from "./styles"
+import Container from "../Container"
+
+const Footer = () => {
+  return (
+    <SC.FooterWrapper>
+      <Container>
+        © {new Date().getFullYear()}, Built with
+        {` `}
+        <a href="https://www.gatsbyjs.org">Gatsby</a>
+      </Container>
+    </SC.FooterWrapper>
+  )
+}
+
+export default Footer

src/components/Footer/styles.tsx

@@ -0,0 +1,4 @@
+import { Link } from "gatsby"
+import styled from "styled-components"
+
+export const FooterWrapper = styled.footer``