update langfield plugin

plugin.xml

@@ -53,8 +53,8 @@
 			<param name="plugin.groupId" value="org/codelibs" />
 			<param name="plugin.name.prefix" value="elasticsearch-" />
 			<param name="plugin.name" value="langfield" />
-			<param name="plugin.version" value="6.4.0" />
-			<param name="plugin.zip.version" value="6.4.0" />
+			<param name="plugin.version" value="6.4.1" />
+			<param name="plugin.zip.version" value="6.4.1" />
 		</antcall>
 		<!-- learning-to-rank -->
 		<antcall target="install.plugin">