fix: issue adopted-ember-addons#277

Author: wozny1989

addon/utils/css-stringify.js

@@ -1,5 +1,6 @@
 import { isEmpty } from '@ember/utils';
-import { dasherize, htmlSafe } from '@ember/string';
+import { dasherize } from '@ember/string';
+import { htmlSafe } from '@ember/template';
 
 const PREFIXES = ['webkit'];
 const PREFIXED_PROPS = [

package.json

@@ -32,6 +32,7 @@
   },
   "dependencies": {
     "@ember/render-modifiers": "^2.0.4",
+    "@ember/string": "^4.0.0",
     "@glimmer/component": "^1.1.2",
     "@glimmer/tracking": "^1.1.2",
     "ember-auto-import": "^2.4.2",

yarn.lock

@@ -1049,6 +1049,11 @@
     ember-cli-babel "^7.26.11"
     ember-modifier-manager-polyfill "^1.2.0"
 
+"@ember/string@^4.0.0":
+  version "4.0.0"
+  resolved "https://registry.yarnpkg.com/@ember/string/-/string-4.0.0.tgz#24fe5cda227c9e6634e6e0b550944a3a13437878"
+  integrity sha512-IMVyVE72twuAMSYcHzWSgtgYTtzlHlKSGW8vEbztnnmkU6uo7kVHmiqSN9R4RkBhzvh0VD4G76Eph+55t3iNIA==
+
 "@ember/test-helpers@^2.7.0":
   version "2.8.1"
   resolved "https://registry.yarnpkg.com/@ember/test-helpers/-/test-helpers-2.8.1.tgz#20f2e30d48172c2ff713e1db7fbec5352f918d4e"