es 6.8.11 support

Author: shi-yuan

.travis.yml

@@ -4,7 +4,7 @@ jdk:
   - openjdk8
 
 before_install:
-  - wget https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-6.8.10.deb && sudo dpkg -i --force-confnew elasticsearch-6.8.10.deb
+  - wget https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-6.8.11.deb && sudo dpkg -i --force-confnew elasticsearch-6.8.11.deb
   - sudo cp ./src/test/resources/elasticsearch.yml /etc/elasticsearch/elasticsearch.yml
   - sudo cat /etc/elasticsearch/elasticsearch.yml
   - sudo java -version

pom.xml

@@ -3,7 +3,7 @@
 	<modelVersion>4.0.0</modelVersion>
 	<groupId>org.nlpcn</groupId>
 	<artifactId>elasticsearch-sql</artifactId>
-	<version>6.8.10.1</version>
+	<version>6.8.11.0</version>
 	<packaging>jar</packaging>
 	<description>Query elasticsearch using SQL</description>
 	<name>elasticsearch-sql</name>
@@ -44,7 +44,7 @@
 		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 		<runSuite>**/MainTestSuite.class</runSuite>
 		<elasticsearch.plugin.name>sql</elasticsearch.plugin.name>
-		<elasticsearch.version>6.8.10</elasticsearch.version>
+		<elasticsearch.version>6.8.11</elasticsearch.version>
 		<elasticsearch.plugin.classname>org.elasticsearch.plugin.nlpcn.SqlPlug</elasticsearch.plugin.classname>
         <druid.version>1.1.16</druid.version>
         <guava.version>15.0</guava.version>