Update JSON:API to ^2.0 and JSON:API Extras to ^3.1 (#343)

Contenta currently requires JSON:API 2.0 at RC. It's now stable. Contenta currently requires JSON:API Extras 3.0. But 3.1 is necessary as of JSON:API 2.0-RC3. So let's bump the minimum to 3.1. (Current stable is 3.2.)

Author: wimleers

composer.json

@@ -53,8 +53,8 @@
     "drupal/entity_browser": "^2.0@alpha",
     "drupal/image_widget_crop": "^2.1",
     "drupal/inline_entity_form": "^1.0@beta",
-    "drupal/jsonapi": "^2.0@rc",
-    "drupal/jsonapi_extras": "^3.0",
+    "drupal/jsonapi": "^2.0",
+    "drupal/jsonapi_extras": "^3.1",
     "drupal/jsonrpc": "^1.0@beta",
     "drupal/material_admin": "^1.0@alpha",
     "drupal/media_entity_browser": "^2.0@alpha",