[GLUTEN-7224][CH]Update ClickHouse.md (apache#7230)

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(Please fill in changes proposed in this fix)

Fixes: apache#7224

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docs/get-started/ClickHouse.md

@@ -77,6 +77,7 @@ checkout to the latest branch
 
 ```shell
 latest_branch=$(cat $gluten_root/cpp-ch/clickhouse.version  | grep CH_BRANCH | cut -d= -f2)
+git fetch origin $latest_branch
 git checkout -b $latest_branch origin/$latest_branch
 git submodule sync --recursive
 git submodule update --init --recursive