Resolve borrow_deref_ref clippy lint

    error: deref on an immutable reference
       --> src/value/mod.rs:428:45
        |
    428 |             Value::Array(ref array) => Some(&*array),
        |                                             ^^^^^^^
        |
        = note: `-D clippy::borrow-deref-ref` implied by `-D clippy::all`
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#borrow_deref_ref
    help: if you would like to reborrow, try removing `&*`
        |
    428 |             Value::Array(ref array) => Some(array),
        |                                             ~~~~~
    help: if you would like to deref, try using `&**`
        |
    428 |             Value::Array(ref array) => Some(&**array),
        |                                             ~~~~~~~~

src/value/mod.rs

@@ -425,7 +425,7 @@ impl Value {
     /// ```
     pub fn as_array(&self) -> Option<&Vec<Value>> {
         match *self {
-            Value::Array(ref array) => Some(&*array),
+            Value::Array(ref array) => Some(array),
             _ => None,
         }
     }