fix #55 with dirty fields (#56)

Author: bluebill1049

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@hookform/devtools",
-  "version": "2.2.0",
+  "version": "2.2.1-beta.1",
   "description": "React Hook Form dev tool to help debugging forms",
   "main": "dist/index.js",
   "umd:main": "dist/index.umd.development.js",

src/panel.tsx

@@ -113,8 +113,7 @@ export default ({
             const type = get(value, 'ref.type', undefined);
             const isTouched = !!get(formStateRef.current.touched, name);
             const isNative = (value as any).ref.type;
-            const isDirty = !!Object.keys(formStateRef.current.dirtyFields)
-              .length;
+            const isDirty = !!get(formStateRef.current.dirtyFields, name);
             const hasError = !!error;
             const ref = get(value, 'ref');