lib: Fix msrv build.
lib: Fix msrv build.

error[E0277]: the trait bound `std::string::String: std::convert::From<&std::string::String>` is not satisfied
   --> src/lib.rs:460:37
    |
460 |             output_vector.push(line.into());
    |                                     ^^^^ the trait `std::convert::From<&std::string::String>` is not implemented for `std::string::String`

rust-lang/rust-bindgen,rust-lang/rust-bindgen,rust-lang/rust-bindgen,rust-lang/rust-bindgen