Add button component test

website/src/components/Button.cy.tsx

@@ -0,0 +1,9 @@
+import React from "react";
+import { Button } from "./Button";
+
+describe("<Button />", () => {
+  it("renders", () => {
+    // see: https://on.cypress.io/mounting-react
+    cy.mount(<Button className="border-gray-300">Test button</Button>);
+  });
+});