Include LICENSE file

This is required by the MIT license terms and needed for shipping
`tree-sitter-fsharp` in distributions like Fedora

```
❯ cargo package --allow-dirty --list | grep LICENSE
LICENSE
```

Signed-off-by: Michel Lind <[email protected]>

Author: michel-slm

Cargo.toml

@@ -10,6 +10,7 @@ license = "MIT"
 
 build = "bindings/rust/build.rs"
 include = [
+  "LICENSE",
   "bindings/rust/*",
   "common",
   "fsharp/grammar.js",