docs: document the rest of crates-io infra

Signed-off-by: MarcoIeni <11428655+MarcoIeni@users.noreply.github.com>

service-catalog/crates-io/README.md

@@ -14,9 +14,18 @@ Here are the details of the crates.io infrastructure managed by the infra team:
 - [crates-io-logs](https://github.com/rust-lang/simpleinfra/tree/master/terragrunt/modules/crates-io-logs):
   the infrastructure that counts crates downloads.
   It is deployed in the AWS accounts `crates-io-prod` and `crates-io-staging`.
+- [crates-io](https://github.com/rust-lang/simpleinfra/tree/master/terragrunt/modules/crates-io): Terraform module for the crates.io infrastructure.
+- [crates-io-heroku-metrics](https://github.com/rust-lang/simpleinfra/tree/master/terraform/crates-io-heroku-metrics):
+  Terraform module that deploys the Heroku metrics [collector](https://github.com/rust-lang/crates-io-heroku-metrics) used to gather crates.io's metrics.
 
 ## Versions
 
 These are the versions we need to keep up-to-date:
 
 - Terraform providers in `simpleinfra` repo.
+- Rust dependencies in the
+  [Cargo.toml](https://github.com/rust-lang/simpleinfra/blob/master/terragrunt/modules/crates-io/compute-static/Cargo.toml)
+  of the fastly CDN (`Compute@Edge`).
+- crates-io-heroku-metrics [Dockerfile](https://github.com/rust-lang/crates-io-heroku-metrics/blob/main/Dockerfile):
+  - Ubuntu.
+  - Vector.