retroarch: fix editorconfig error on hashes.json

pkgs/misc/emulators/retroarch/hashes.json

···
         "sha256": "VstPh0oMEZ7/ts58NjZxBYZZx/7dRTYePhDIQMu0WOo=",
         "fetchSubmodules": false
     }
-}
+}

pkgs/misc/emulators/retroarch/update.py

···
     info(f"Generating '{HASHES_PATH}'...")
     with open(HASHES_PATH, "w") as f:
         f.write(json.dumps(repo_hashes, indent=4))
+        f.write("\n")
     info("Finished!")