update release guide

community/content/contribute/release.cn.md

@@ -147,9 +147,8 @@ https://github.com/apache/incubator-shardingsphere/blob/dev/RELEASE-NOTES.md
 ```shell
 cd ~/incubator-shardingsphere/
 git pull
-git branch ${RELEASE.VERSION}-release
+git checkout -b ${RELEASE.VERSION}-release
 git push origin ${RELEASE.VERSION}-release
-git checkout ${RELEASE.VERSION}-release
 ```
 
 ### 发布预校验

community/content/contribute/release.en.md

@@ -149,9 +149,8 @@ Create `${RELEASE.VERSION}-release` branch, where all the following operations a
 ```shell
 cd ~/incubator-shardingsphere/
 git pull
-git branch ${RELEASE.VERSION}-release
+git checkout -b ${RELEASE.VERSION}-release
 git push origin ${RELEASE.VERSION}-release
-git checkout ${RELEASE.VERSION}-release
 ```
 
 ### Pre-Release Check