add code group dropdowns

Author: dks333

components/code-groups.mdx

@@ -28,6 +28,32 @@ class HelloWorld {
 
 </CodeGroup>
 
+### Dropdown
+
+You can also show a dropdown button to toggle the code groups with languages as the options.
+
+<CodeGroup dropdown>
+
+```javascript helloWorld.js
+console.log("Hello World");
+```
+
+```python hello_world.py
+print('Hello World!')
+```
+
+```java HelloWorld.java
+class HelloWorld {
+    public static void main(String[] args) {
+        System.out.println("Hello, World!");
+    }
+}
+```
+
+</CodeGroup>
+
+
+
 <RequestExample>
 
 ````mdx Code Group Example
@@ -53,3 +79,10 @@ class HelloWorld {
 ````
 
 </RequestExample>
+
+### Props
+
+<ResponseField name="dropdown" type="boolean">
+  Whether to show a dropdown button to toggle the code groups with languages as the options.
+</ResponseField>
+