Fix fs_root computation

Author: willcrichton

crates/depot/src/workspace/mod.rs

@@ -204,7 +204,7 @@ impl Workspace {
       Some(cwd) => cwd,
       None => env::current_dir()?,
     };
-    let fs_root = cwd.ancestors().next().unwrap().to_path_buf();
+    let fs_root = cwd.ancestors().last().unwrap().to_path_buf();
     let git_root = utils::get_git_root(&cwd);
     let max_ancestor: &Path = git_root.as_deref().unwrap_or(&fs_root);
     let root = find_workspace_root(max_ancestor, &cwd)?;