update license badge

Author: bashandbone

README.md

@@ -2,7 +2,7 @@
 
 [![Crates.io](https://img.shields.io/crates/v/submod.svg)](https://crates.io/crates/submod)
 [![Documentation](https://docs.rs/submod/badge.svg)](https://docs.rs/submod)
-[![License](https://img.shields.io/badge/license-MIT%2FApache--2.0-blue.svg)](LICENSE)
+[![Static Badge](https://img.shields.io/badge/Plain-MIT-15db95?style=flat-square&labelColor=0d19a3&cacheSeconds=86400&link=https%3A%2F%2Fplainlicense.org%2Flicenses%2Fpermissive%2Fmit%2Fmit%2F)](https://plainlicense.org/licenses/permissive/mit/)
 [![Rust](https://img.shields.io/badge/rust-1.87%2B-blue.svg)](https://www.rust-lang.org)
 
 A lightweight, fast CLI tool for managing git submodules with advanced sparse checkout support. Built on top of `gitoxide` and `git2` libraries for maximum performance and reliability.