update README.md

Author: shi-yuan

README.md

@@ -103,6 +103,8 @@ Elasticsearch-SQL
 <br/>
 **6.7.2** [![6.7.2 Build Status](https://travis-ci.org/NLPchina/elasticsearch-sql.svg?branch=elastic6.7.2)](https://travis-ci.org/NLPchina/elasticsearch-sql)
 **6.8.0** [![6.8.0 Build Status](https://travis-ci.org/NLPchina/elasticsearch-sql.svg?branch=elastic6.8.0)](https://travis-ci.org/NLPchina/elasticsearch-sql)
+**6.8.1** [![6.8.1 Build Status](https://travis-ci.org/NLPchina/elasticsearch-sql.svg?branch=elastic6.8.1)](https://travis-ci.org/NLPchina/elasticsearch-sql)
+**6.8.2** [![6.8.2 Build Status](https://travis-ci.org/NLPchina/elasticsearch-sql.svg?branch=elastic6.8.2)](https://travis-ci.org/NLPchina/elasticsearch-sql)
 
 Query elasticsearch using familiar SQL syntax.
 You can also use ES functions in SQL.
@@ -212,6 +214,8 @@ Versions
 | 6.7.1                 | 6.7.1.0        |                                | elastic6.7.1 |
 | 6.7.2                 | 6.7.2.0        |                                | elastic6.7.2 |
 | 6.8.0                 | 6.8.0.0        |                                | elastic6.8.0 |
+| 6.8.1                 | 6.8.1.0        |                                | elastic6.8.1 |
+| 6.8.2                 | 6.8.2.0        |                                | elastic6.8.2 |
 
 ### Elasticsearch 1.x
 ````
@@ -626,6 +630,16 @@ Versions
 ./bin/elasticsearch-plugin install https://github.com/NLPchina/elasticsearch-sql/releases/download/6.8.0.0/elasticsearch-sql-6.8.0.0.zip
 ````
 
+### Elasticsearch 6.8.1
+````
+./bin/elasticsearch-plugin install https://github.com/NLPchina/elasticsearch-sql/releases/download/6.8.1.0/elasticsearch-sql-6.8.1.0.zip
+````
+
+### Elasticsearch 6.8.2
+````
+./bin/elasticsearch-plugin install https://github.com/NLPchina/elasticsearch-sql/releases/download/6.8.2.0/elasticsearch-sql-6.8.2.0.zip
+````
+
 After doing this, you need to restart the Elasticsearch server. Otherwise you may get errors like `Invalid index name [sql], must not start with '']; ","status":400}`.
 
 ## Basic Usage