upgrade various Rust dependencies

This stops using parking_lot entirely. Since Rust 1.62, the std
implementations on Linux are direct futexes, not the boxed pthread
mutexes they used to be. No real reason to use parking_lot anymore, so
shed this dependency.

server/db/upgrade/v1_to_v2.rs

@@ -323,7 +323,7 @@ fn verify_dir_contents(
             Ok(u) => u,
             Err(_) => bail!("unexpected file {:?} in {:?}", f, sample_file_path),
         };
-        if s != uuid.to_hyphenated_ref().to_string() {
+        if s != uuid.as_hyphenated().to_string() {
             // non-canonical form.
             bail!("unexpected file {:?} in {:?}", f, sample_file_path);
         }