instead of stringyfied key

The queryMixin assumes query results are named items.
It's already customary in other queries.
Dynamically detecting and adapting the item name is not possible.

Resolve "Adapt to Core 4.0"

Closes #247

See merge request !335

Update .eslintrc.js

See merge request !333

Update .gitignore

See merge request !348

Update .prettierignore

See merge request !349

Update tox.ini

See merge request !343