[maven-release-plugin] copy for tag java-sdk-0.2.1

[maven-release-plugin] copy for tag java-sdk-0.2.0

Merge pull request leancloud#23 from daweibayu/bump_version

bump version

Merge pull request leancloud#10 from lbt05/master

更新环境设置的相关代码

Merge pull request leancloud#7 from lbt05/master

change env setting behavior