feat: export middleware module from stream-chat

Author: MartinCupela

src/index.ts

@@ -8,6 +8,7 @@ export * from './connection';
 export * from './events';
 export * from './insights';
 export * from './messageComposer';
+export * from './middleware';
 export * from './moderation';
 export * from './permissions';
 export * from './poll';