Replace tempdir with tempfile

Summary:
`tempdir` has been deprecated since 2018:
rust-lang-deprecated/tempdir#46

It's functionality was merged into `tempfile` with minor tweaks:

- Methods names: `new` -> `with_prefix`, `new_in` -> `with_prefix_in`.
- `with_prefix_in`'s args order is reversed.
- Temp dirs no longer have a period between the prefix and the random
  name (before `foo.123abc`, now `foo123abc`).

Reviewed By: capickett

Differential Revision: D50514209

fbshipit-source-id: a50e9f1c0c78a2642bae8edbb6098b3f04c89969

shed/chrome_trace/Cargo.toml

@@ -21,4 +21,4 @@ zstd = { version = "0.13", features = ["experimental", "zstdmt"] }
 
 [dev-dependencies]
 maplit = "1.0"
-tempdir = "0.3"
+tempfile = "3.5"

shed/chrome_trace/src/lib.rs

@@ -593,7 +593,7 @@ mod tests {
         trace.add_event(begin.clone());
         trace.add_event(end.clone());
 
-        let tmp = tempdir::TempDir::new("trace-event").unwrap();
+        let tmp = tempfile::TempDir::with_prefix("trace-event.").unwrap();
         let path = tmp.path().join("trace.json");
 
         trace.save(&path).expect("Failed to save trace");
@@ -627,7 +627,7 @@ mod tests {
         trace.add_event(begin.clone());
         trace.add_event(end.clone());
 
-        let tmp = tempdir::TempDir::new("trace-event").unwrap();
+        let tmp = tempfile::TempDir::with_prefix("trace-event.").unwrap();
         let path = tmp.path().join("trace.json.gz");
 
         trace.save_gzip(&path).expect("Failed to save trace");
@@ -661,7 +661,7 @@ mod tests {
         trace.add_event(begin.clone());
         trace.add_event(end.clone());
 
-        let tmp = tempdir::TempDir::new("trace-event").unwrap();
+        let tmp = tempfile::TempDir::with_prefix("trace-event.").unwrap();
         let path = tmp.path().join("trace.json.zst");
 
         trace.save_zstd(&path).expect("Failed to save trace");