Resolves clippy errors (#128)

src/steps/os/archlinux.rs

@@ -245,7 +245,7 @@ impl Aura {
 
 impl ArchPackageManager for Aura {
     fn upgrade(&self, ctx: &ExecutionContext) -> Result<()> {
-        let sudo = which("sudo").unwrap_or(PathBuf::new());
+        let sudo = which("sudo").unwrap_or_else(PathBuf::new);
         let mut aur_update = ctx.run_type().execute(&sudo);
 
         if sudo.ends_with("sudo") {

src/steps/tmux.rs

@@ -84,7 +84,7 @@ pub fn run_in_tmux(args: Vec<String>) -> ! {
         shell_words::join(command)
     };
 
-    let tmux = Tmux::new(args.clone());
+    let tmux = Tmux::new(args);
 
     if !tmux.has_session("topgrade").expect("Error detecting a tmux session") {
         tmux.new_session("topgrade").expect("Error creating a tmux session");