Type-cast the Pipeline object in JedisSentineled (#3517)

This is an expansion of #3221, as well as #3240. This is requested in #3516.

Author: sazzad16

src/main/java/redis/clients/jedis/JedisSentineled.java

@@ -24,4 +24,9 @@ public JedisSentineled(SentineledConnectionProvider sentineledConnectionProvider
   public HostAndPort getCurrentMaster() {
     return ((SentineledConnectionProvider) provider).getCurrentMaster();
   }
+
+  @Override
+  public Pipeline pipelined() {
+    return (Pipeline) super.pipelined();
+  }
 }