chore: Enable clippy pathbuf_init_then_push lint (#2324)

And fix the warnings.

Author: larseggert

Cargo.toml

@@ -44,6 +44,7 @@ nursery = { level = "warn", priority = -1 }
 pedantic = { level = "warn", priority = -1 }
 if_then_some_else_none = "warn"
 get_unwrap = "warn"
+pathbuf_init_then_push = "warn"
 
 # Optimize build dependencies, because bindgen and proc macros / style
 # compilation take more to run than to build otherwise.

neqo-bin/src/lib.rs

@@ -276,8 +276,7 @@ mod tests {
 
     impl TempDir {
         fn new() -> Self {
-            let mut dir = std::env::temp_dir();
-            dir.push(format!(
+            let dir = std::env::temp_dir().join(format!(
                 "neqo-bin-test-{}",
                 SystemTime::now()
                     .duration_since(SystemTime::UNIX_EPOCH)