[Enhancement] Run `cargo update` automatically on lockfiles in `aws/sdk/benchmarks`

[ysaito1001]

We added lockfiles for benchmark crates in aws/sdk/benchmarks (PR)

We should either

• update the cargoUpdateAllLockfiles gradle task to handle lockfiles in aws/sdk/benchmarks.
  or
• create a separate gradle task and let CI scripts invoke that task separately.

Whatever approach we end up with, we should employ the same solution for #4205.