Add the file to tsconfig.json to avoid test failure

types/react-big-calendar/tsconfig.json

@@ -20,6 +20,7 @@
     },
     "files": [
         "index.d.ts",
-        "react-big-calendar-tests.tsx"
+        "react-big-calendar-tests.tsx",
+        "lib/addons/dragAndDrop.d.ts"
     ]
-}
+}