message: examples: use `tempfile` in`fmt-multiple-writers`
  Whoops, this example _also_ uses `tempdir`. My bad!
diff: mod yak_shave;
  use std::io;
  -use tempdir::TempDir;
  use tracing_subscriber::{fmt, subscribe::CollectExt, EnvFilter};
  fn main() {
  - let dir = TempDir::new("directory").expect("Failed to create tempdir");
  + let dir = tempfile::tempdir().expect("Failed to create tempdir");
  let file_appender = tracing_appender::rolling::hourly(dir, "example.log");
  let (non_blocking, _guard) = tracing_appender::non_blocking(file_appender);
  