fix: remove unneeded extra allocation

cli/src/config.rs

···
 #[derive(Debug, serde::Deserialize)]
 pub struct Entry {
     pub name: String,
-    pub keys: Box<[Box<Source>]>,
+    pub keys: Box<[Source]>,
 }
 
 impl Entry {
···
 
 impl Config {
     pub fn fetch(&self) -> Result<Output, ()> {
-        let keys = self.entries.par_iter().map(Entry::fetch).collect();
+        let keys = self.entries.into_par_iter().map(Entry::fetch).collect();
 
         Ok(Output { keys })
     }