Upgrade spawned-concurrency and spawned-rt to 0.5.0 from crates.io (#224)

## Motivation

We've been depending on `spawned-concurrency` and `spawned-rt` via a git
tag (`v0.5.0-rc2`). The stable `0.5.0` release is now published on
crates.io, so we can switch to the registry dependency — cleaner, faster
to resolve, and easier for downstream consumers.

## Description

Updates the workspace `Cargo.toml` to pull both crates from crates.io
instead of the git repository:

| Crate | Before | After |
|-------|--------|-------|
| `spawned-concurrency` | `git = "...spawned.git", tag = "v0.5.0-rc2"` |
`"0.5.0"` |
| `spawned-rt` | `git = "...spawned.git", tag = "v0.5.0-rc2"` |
`"0.5.0"` |

No code changes were needed — the upgrade from RC2 to stable introduced
no breaking changes.

## How to Test

- `make fmt` — passes
- `make lint` — passes (no new warnings)
- `make test` — all workspace tests pass

Congrats on the 0.5.0 release! 🎉

Author: pablodeymo

Cargo.lock

@@ -46,8 +46,8 @@ serde_json = "1.0.117"
 serde_yaml_ng = "0.10"
 hex = "0.4"
 
-spawned-concurrency = { git = "https://github.com/lambdaclass/spawned.git", tag = "v0.5.0-rc2" }
-spawned-rt = { git = "https://github.com/lambdaclass/spawned.git", tag = "v0.5.0-rc2" }
+spawned-concurrency = "0.5.0"
+spawned-rt = "0.5.0"
 tokio = "1.0"
 
 prometheus = "0.14"