ember-polyfills.deprecate-assign deprication in Ember 4.4

I am currently upgrading Ember version to `4.4` and now i get this depreciation with id `ember-polyfills.deprecate-assign` 

Seems it comes from `ember-fetch/addon/utils/mung-options-for-fetch.ts`

More info: https://deprecations.emberjs.com/v4.x/

versions
`ember-simple-auth`: `4.2.2`
`ember-source` and `ember-cli`: `4.4.0`
`npm`: `16.14.0`
`node`: `8.3.1`