fix(deprecation): WarpDrive/EmberData no longer uses ember-inflector for irregular rules

Please `import { irregular } from '@ember-data/request-utils/string';`
instead to register a custom irregular rule for use with EmberData.
[deprecation id: warp-drive.ember-inflector] This will be removed in
warp-drive 6.0.0.

Author: eth3lbert

app/models/dependency.js

@@ -1,8 +1,7 @@
 import Model, { attr, belongsTo } from '@ember-data/model';
+import { irregular } from '@ember-data/request-utils/string';
 
-import Inflector from 'ember-inflector';
-
-Inflector.inflector.irregular('dependency', 'dependencies');
+irregular('dependency', 'dependencies');
 
 export default class Dependency extends Model {
   @attr crate_id;