Add property autoload to ReactAsyncSelectProps. (#14936)

react-select/index.d.ts

@@ -397,6 +397,11 @@ declare namespace ReactSelectClass {
 
 
     export interface ReactAsyncSelectProps extends ReactSelectProps {
+        /**
+         * Whether to auto-load the default async options set.
+         */
+        autoload?: boolean;
+
         /**
          *  object to use to cache results; can be null to disable cache
          */