chore: bump version to 1.3.0

Author: skyline69

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "agcp"
-version = "1.2.3"
+version = "1.3.0"
 edition = "2024"
 rust-version = "1.93"
 description = "Lightweight Rust proxy translating Anthropic Claude API to Google Cloud Code API"