fix: assure build-script is added to the package (#1572)

Otherwise, the `GIX_VERSION` environment variable is not available at build time,
which can lead to runtime errors.

Author: Byron

Cargo.toml

@@ -9,7 +9,7 @@ edition = "2021"
 license = "MIT OR Apache-2.0"
 version = "0.38.0"
 default-run = "gix"
-include = ["src/**/*", "LICENSE-*", "README.md"]
+include = ["src/**/*", "/build.rs", "LICENSE-*", "README.md"]
 resolver = "2"
 
 [[bin]]