Upgrade default function extension bundle to v3

azure-functions-gradle-plugin/src/main/java/com/microsoft/azure/plugin/functions/gradle/handler/PackageHandler.java

@@ -92,7 +92,7 @@ public class PackageHandler {
     private static final String DEFAULT_LOCAL_SETTINGS_JSON = "{ \"IsEncrypted\": false, \"Values\": " +
         "{ \"FUNCTIONS_WORKER_RUNTIME\": \"java\" } }";
     private static final String DEFAULT_HOST_JSON = "{\"version\":\"2.0\",\"extensionBundle\":" +
-        "{\"id\":\"Microsoft.Azure.Functions.ExtensionBundle\",\"version\":\"[2.*, 3.0.0)\"}}\n";
+        "{\"id\":\"Microsoft.Azure.Functions.ExtensionBundle\",\"version\":\"[3.*, 4.0.0)\"}}\n";
     private static final String TRIGGER_TYPE = "triggerType";
 
     private final IProject project;