Update license in Cargo.toml

Cargo.toml

@@ -7,7 +7,7 @@ description = "Utility to activate escape codes in Windows' CMD and PowerShell"
 repository = "https://github.com/Phundrak/output-vt100-rs"
 keywords = ["vt100", "console", "ansi"]
 readme = "README.md"
-license = "GPL-3.0"
+license = "MIT"
 categories = ["development-tools"]
 
 [dependencies]