Fix posresolution type error by converting integers to floats

Add posresolution and rain_midnight to the list of float fields in
normalize_numeric_types to ensure integer values are converted to floats
before database insertion. This fixes the Ecto.ChangeError that was
preventing many APRS packets from being stored in the database.

lib/aprsme/packet_consumer.ex

@@ -656,7 +656,9 @@ defmodule Aprsme.PacketConsumer do
       :rain_since_midnight,
       :snow,
       :speed,
-      :altitude
+      :altitude,
+      :posresolution,
+      :rain_midnight
     ]
 
     Enum.reduce(float_fields, attrs, fn field, acc ->