docs: docker build error

[totalo]

Changes proposed in this pull request:

• There are some errors in the docker help document, and I tried to fix it

[terrymanu]

The correct project name is shardingsphere-proxy.
It is unnecessary to change here.

[totalo]

The correct project name is shardingsphere-proxy.
It is unnecessary to change here.

But what the program reads is the configuration in sharding-proxy, mounted to the shardingsphere-proxy directory, the project cannot be started, please check

[terrymanu]

The correct project name is shardingsphere-proxy.
It is unnecessary to change here.

But what the program reads is the configuration in sharding-proxy, mounted to the shardingsphere-proxy directory, the project cannot be started, please check

It seems we need to update the docker file, is it?

[totalo]

The correct project name is shardingsphere-proxy.
It is unnecessary to change here.

But what the program reads is the configuration in sharding-proxy, mounted to the shardingsphere-proxy directory, the project cannot be started, please check

It seems we need to update the docker file, is it?

Yes, let me to fix it.