update .travis.yml

Author: cyilin

.travis.yml

@@ -1,6 +1,6 @@
 language: java
 jdk: oraclejdk8
-before_install: sed -i "s/^\(version:.*\)/\2.$TRAVIS_BUILD_NUMBER/" src/main/resources/plugin.yml
+before_install: sed -i "s/^\(version:.*\)/\1.$TRAVIS_BUILD_NUMBER/" src/main/resources/plugin.yml
 before_deploy:
 - git config --global user.email "builds@travis-ci.com"
 - git config --global user.name "Travis CI"