chore(rust): include license file (tree-sitter-grammars#51)

Author: michel-slm

Cargo.toml

@@ -12,7 +12,7 @@ edition = "2021"
 autoexamples = false
 
 build = "bindings/rust/build.rs"
-include = ["bindings/rust/*", "grammar.js", "queries/*", "src/*"]
+include = ["LICENSE.md", "bindings/rust/*", "grammar.js", "queries/*", "src/*"]
 
 [lib]
 path = "bindings/rust/lib.rs"