feat(client): Adapt thread-safe update client configuration

[0x676e67]

This pull request includes multiple changes to the rquest library, focusing on updating the Client builder usage and improving the API ergonomics. The most important changes include adding the apply method to various client configurations, updating the README.md file, and adding a new dependency in Cargo.toml.

Client Configuration Updates:

• Updated examples/base_url.rs, examples/client_chain.rs, examples/set_cookie_provider.rs, examples/set_headers.rs, examples/set_impersonate.rs, examples/set_interface.rs, examples/set_local_address.rs, examples/set_proxies.rs, and examples/set_redirect.rs to use the apply method after setting client configurations. This ensures that changes are properly applied. [1] [2] [3] [4] [5] [6] [7] [8] [9]

Dependency Addition:

• Added arc-swap version 1.7.0 to Cargo.toml to manage atomic reference counting for shared data.

Documentation Updates:

• Updated README.md to improve the licensing section and remove redundant learning resources. [1] [2]

Code Simplification:

• Simplified client creation by removing unnecessary mut declarations in various example files. [1] [2] [3] [4] [5] [6] [7] [8] [9]