Implement wildcard matcher for arrays

Spec https://jsonpath-standard.github.io/internet-draft/#section-2.6.1

```
A dot child name consisting of a single asterisk is a wild card. It selects all the values of any object node. It also selects all the elements of any array node. It selects no nodes from number, string, or literal nodes.
```

Author: Marko Mikulicic

src/matchers.rs

@@ -33,10 +33,10 @@ pub struct WildcardedChild {}
 
 impl Matcher for WildcardedChild {
     fn select<'a>(&self, node: &'a Value) -> Iter<'a> {
-        if let Some(m) = node.as_object() {
-            Box::new(m.values())
-        } else {
-            Box::new(iter::empty())
+        match node {
+            Value::Object(m) => Box::new(m.values()),
+            Value::Array(a) => Box::new(a.iter()),
+            _ => Box::new(iter::empty()),
         }
     }
 }
@@ -75,3 +75,25 @@ impl Matcher for Union {
         Box::new(self.elements.iter().flat_map(move |it| it.select(node)))
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use serde_json::{json, Value};
+
+    #[test]
+    fn object_wildcard() {
+        let s = WildcardedChild {};
+        let j = json!({"a": 1, "b": 2});
+        let r: Vec<&Value> = s.select(&j).collect();
+        assert_eq!(format!("{:?}", r), "[Number(1), Number(2)]");
+    }
+
+    #[test]
+    fn array_wildcard() {
+        let s = WildcardedChild {};
+        let j = json!([1, 2]);
+        let r: Vec<&Value> = s.select(&j).collect();
+        assert_eq!(format!("{:?}", r), "[Number(1), Number(2)]");
+    }
+}

tests/cts.json

@@ -37,7 +37,7 @@
     "name": "wildcarded child of array",
     "selector": "$.*",
     "document": ["first", "second"],
-    "result": []
+    "result": ["first", "second"]
   }, {
     "name": "wildcarded child dot child",
     "selector": "$.*.a",