Doc.rs built document fail

[yanganto]

The problem is that Doc.rs are building doc in an isolated container without network access.

[INFO] [stderr] error: failed to run custom build command for `ssvm-evmc-client v6.3.1-rc4`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `/opt/rustwide/target/debug/build/ssvm-evmc-client-e5797a5e1d9848c8/build-script-build` (exit status: 101)
[INFO] [stderr]   --- stderr
[INFO] [stderr]   fatal: could not create leading directories of '/opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/ssvm-evmc-client-6.3.1-rc4/target/evmc-6.3.1-rc4-crates': Read-only file system
[INFO] [stderr]   thread 'main' panicked at 'failed to execute "git" "clone" "--branch=6.3.1-rc4-crates" "--recursive" 

[yanganto]

Base on this issue
rust-lang/docs.rs#806 (comment)

It is good to use git submodule in ssvm-evmc-client to fix this problem.

[yanganto]

This issue is pendding, please click SewUpDoc badge in the README to see the latest documentation. Currrently, we are not hurry to fix this up.

[yanganto]

Currently, sewup dependent on ssvm-evmc-client (6.3.1-rc4). This issue can be fixed with the solution that tensorflow did
tensorflow/rust#255 (comment)

However, we need to update the legacy dependency of ssvm-evmc-client, and also rust-ssvm before we introduce this solution.

Following are action items we need to do

• update svm-evmc-client and rust-ssvm Update svm-evmc-client and rust-ssvm #276
• use a feature to prevent doc issue
• release new version