chore(Echo): relax dev dependency versions in docs

- Updated dependency badges in README to use latest versions without pinning
- Changed Cargo.toml examples to wildcard versions for easier contributor onboarding

This aligns documentation with Land's development practices where Echo (Mountain's concurrency runtime) should be tested against latest dependency versions to ensure compatibility with Mountain's native backend. The change supports ongoing scheduler optimizations seen in recent refactor commits while maintaining architectural flexibility for future Crossbeam/Tokio updates.

Author: NikolaRHristov

README.md

@@ -14,7 +14,7 @@
 [![License: CC0-1.0](https://img.shields.io/badge/License-CC0_1.0-lightgrey.svg)](https://github.com/CodeEditorLand/Echo/tree/Current/LICENSE)
 [![Crates.io](https://img.shields.io/crates/v/Echo.svg)](https://crates.io/crates/Echo)
 [![Tokio Version](https://img.shields.io/badge/Tokio-v1-blue.svg)](https://tokio.rs/)
-[![Crossbeam Version](https://img.shields.io/badge/Crossbeam-v0.8-blueviolet.svg)](https://github.com/crossbeam-rs/crossbeam)
+[![Crossbeam Version](https://img.shields.io/badge/Crossbeam-blueviolet.svg)](https://github.com/crossbeam-rs/crossbeam)
 
 Welcome to **Echo**! This crate provides a powerful, structured concurrency
 runtime for Rust applications, built on a high-performance **work-stealing
@@ -146,11 +146,11 @@ Echo = { git = "https://github.com/CodeEditorLand/Echo.git", branch = "Current"
 
 **Key Dependencies:**
 
-- `tokio = { version = "1", features = ["full"] }`
-- `crossbeam-deque = "0.8"`
-- `rand = "0.8"`
-- `log = "0.4"`
-- `num_cpus = "1.0"`
+- `tokio = { version = "*", features = ["full"] }`
+- `crossbeam-deque = "*"`
+- `rand = "*"`
+- `log = "*"`
+- `num_cpus = "*"`
 
 ### Usage