bump version travis uses for test

Author: fxdgear

.travis.yml

@@ -24,7 +24,7 @@ before_install:
  - java -version
 
 install:
- - curl -L -o /tmp/es-snap.zip https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-6.0.0.zip
+ - curl -L -o /tmp/es-snap.zip https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-6.1.1.zip
  - unzip /tmp/es-snap.zip -d /tmp/
  - /tmp/elasticsearch-*/bin/elasticsearch -E path.repo=/tmp -E repositories.url.allowed_urls='http://*' -E node.attr.testattr=test -d
  - git clone https://github.com/elastic/elasticsearch.git ../elasticsearch