Fix jpn wording

Author: oppara

src/languages/jpn.json

@@ -1,5 +1,5 @@
 {
-    "old_version": "新しい",
-    "new_version": "古い",
+    "old_version": "古い",
+    "new_version": "新しい",
     "differences": "差異"
 }