update pmp-protobuf - fix custom object serialization

Author: Ianyourgod

package-lock.json

@@ -59,7 +59,7 @@
         "omggif": "1.0.9",
         "papaparse": "5.3.0",
         "PenguinMod-MarkDown": "github:PenguinMod/PenguinMod-MarkDown#master",
-        "pmp-protobuf": "^1.7.3",
+        "pmp-protobuf": "^1.8.3",
         "postcss-import": "^12.0.1",
         "postcss-loader": "^3.0.0",
         "postcss-simple-vars": "^5.0.2",