Update README.md

Author: mehm8128

README.md

@@ -1,2 +1,13 @@
 # queryByRole
 This is a implementation of `queryByRole` for browser.
+
+## Usage
+
+You'll get the button whose accessible name is "Click!" from window with the following code.
+```ts
+const targetWindow = createTargetWindow(window);
+const buttonRoleElements = targetWindow.queryByRole("button", {
+  name: "Click!",
+});
+console.log(buttonRoleElements); // -> [button]
+```