Delete no-longer-used build.rs

build.rs

-use vergen::{ConstantsFlags, generate_cargo_keys};
-
-const ERROR_MSG: &str = "Failed to generate metadata files";
-
-fn main() {
-	generate_cargo_keys(ConstantsFlags::SHA_SHORT).expect(ERROR_MSG);
-
-	build_script_utils::rerun_if_git_head_changed();
-}