Update html for new companion board

Author: tyeth

index.html

@@ -314,7 +314,7 @@ <h2>2. Select Companion Board (Optional)</h2>
                 <option value="microsd-bff">Adafruit microSD Card BFF Add-On for QT Py and Xiao</option>
                 <option value="winc1500-shield">Adafruit WINC1500 WiFi Shield</option>
                 <option value="airlift-shield">Adafruit AirLift Shield - ESP32 WiFi Co-Processor</option>
-
+                <option value="seeed-xiao-ssd1306-expansion-base">Seeed Studio XIAO Expansion base board</option>
             </select>
 
             <div id="companion-details" class="hidden">