fix: linux file watching did not detect recreate

The notify crate does not properly handle watching of recreated files on
all platform. This commit instead watches the parent directory as
proposed in the documentation of Notify.

See: notify-rs/notify#166

crates/mun_runtime/src/lib.rs

@@ -131,7 +131,7 @@ impl Runtime {
         assembly.link(&self.dispatch_table)?;
 
         self.watcher
-            .watch(library_path.clone(), RecursiveMode::NonRecursive)?;
+            .watch(library_path.parent().unwrap(), RecursiveMode::NonRecursive)?;
 
         self.assemblies.insert(library_path, assembly);
         Ok(())