Resolve cloned_instead_of_copied pednatic clippy lint

    warning: used `cloned` where `copied` could be used instead
      --> src/de.rs:46:29
       |
    46 |         self.tokens.first().cloned()
       |                             ^^^^^^ help: try: `copied`
       |
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#cloned_instead_of_copied
       = note: `-W clippy::cloned-instead-of-copied` implied by `-W clippy::pedantic`

src/de.rs

@@ -43,7 +43,7 @@ impl<'de> Deserializer<'de> {
  }
 
  fn peek_token_opt(&self) -> Option<Token> {
- self.tokens.first().cloned()
+ self.tokens.first().copied()
  }
 
  fn peek_token(&self) -> Result<Token, Error> {

src/lib.rs

@@ -149,7 +149,6 @@
 #![allow(clippy::float_cmp, clippy::needless_doctest_main)]
 // Ignored clippy_pedantic lints
 #![allow(
- clippy::cloned_instead_of_copied,
  clippy::manual_assert,
  clippy::missing_panics_doc,
  clippy::module_name_repetitions,