Using enzyme-to-json to get better diff snapshots

[patw0929]

We can use enzyme-to-json to generate better diff snapshots like following case:

-exports[`<A /> snapshots should match latest mount snapshot 1`] = `"<div><h1 style=\\"display: none;\\">title</h1><button class=\\"btn-foo\\">click me</button><button class=\\"btn-bar\\">click me</button><nav><a href=\\"#\\"><!-- react-text: 7 -->I am link <!-- /react-text --><!-- react-text: 8 -->0<!-- /react-text --><!-- react-text: 9 -->.<!-- /react-text --></a><a href=\\"#\\"><!-- react-text: 11 -->I am link <!-- /react-text --><!-- react-text: 12 -->1<!-- /react-text --><!-- react-text: 13 -->.<!-- /react-text --></a><a href=\\"#\\"><!-- react-text: 15 -->I am link <!-- /react-text --><!-- react-text: 16 -->2<!-- /react-text --><!-- react-text: 17 -->.<!-- /react-text --></a></nav></div>"`;
+exports[`<A /> snapshots should match latest mount snapshot 1`] = `
+<A
+  bar={[Function]}
+>
+  <div>
+    <h1
+      style={
+        Object {
+          "display": "none",
+        }
+      }
+    >
+      title
+    </h1>
+    <button
+      className="btn-foo"
+      onClick={[Function]}
+    >
+      click me
+    </button>
+    <button
+      className="btn-bar"
+      onClick={[Function]}
+    >
+      click me
+    </button>
...

Thanks.