make localforage.config fail if version is not a number

make localforage.config fail if version is not a number: a task in MiMo-V2.6-RL-harbor-code: MiMo-V2.6-RL Code (Harbor) (Harbor dataset). My fault, but it would be helpful to have localforage.config fail if the version number is a string. Why? IndexedDB in FF and Chrome will be happy with "1.0" …

The task

My fault, but it would be helpful to have `localforage.config` fail if the version number is a string. Why? IndexedDB in FF and Chrome will be happy with `"1.0"`, but IE's IndexedDB will throw `InvalidAccessError`.

Part of FineEnvs/MiMo-V2.6-RL-harbor-code.