`editorconfig-core` is not `require`d by default

[chvp]

With

(use-package editorconfig
  :ensure t
  :config (editorconfig-mode 1)
  )

I get Warning (editorconfig): Failed to get properties, styles will not be applied: (editorconfig-error "Invalid editorconfig-get-properties-function value"), and the editorconfig settings are not applied.

With

(use-package editorconfig
  :ensure t
  :config
  (require 'editorconfig-core)
  (editorconfig-mode 1)
  )

no such warning is triggered, and the editorconfig settings are applied.