Delete 2 legacy branches in apache/shardingsphere

[吴伟杰]

Hi community,

I think the following branches can be deleted:
- https://github.com/apache/shardingsphere/tree/opengauss_adapt
- https://github.com/apache/shardingsphere/tree/revert-11082-fix/docker-readme

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Sincerely,
Weijie Wu (TeslaCN)
Apache ShardingSphere