fix typescript error

Fix the following typescript error:

> Type '(conventions: DocumentConventions) => RavenCommand<boolean>' is
not assignable to type '(conventions: DocumentConventions) =>
RavenCommand<Boolean>'.
> Call signature return types 'RavenCommand<boolean>' and
'RavenCommand<Boolean>' are incompatible.
> Type 'Boolean' is not assignable to type 'boolean'.
> 'boolean' is a primitive, but 'Boolean' is a wrapper object.

src/Documents/Operations/Indexes/IndexHasChangedOperation.ts

@@ -8,7 +8,7 @@ import { HttpRequestParameters } from "../../../Primitives/Http";
 import { HeadersBuilder } from "../../../Utility/HttpUtil";
 import * as stream from "readable-stream";
 
-export class IndexHasChangedOperation implements IMaintenanceOperation<Boolean> {
+export class IndexHasChangedOperation implements IMaintenanceOperation<boolean> {
 
     private readonly _definition: IndexDefinition;