build(deps-dev): bump eslint from 6.3.0 to 6.4.0

Bumps [eslint](https://github.com/eslint/eslint) from 6.3.0 to 6.4.0.
- [Release notes](https://github.com/eslint/eslint/releases)
- [Changelog](https://github.com/eslint/eslint/blob/master/CHANGELOG.md)
- [Commits](eslint/eslint@v6.3.0...v6.4.0)

Signed-off-by: dependabot-preview[bot] <[email protected]>

package.json

@@ -45,7 +45,7 @@
     "ember-source": "~3.12.0",
     "ember-source-channel-url": "^2.0.1",
     "ember-try": "^1.2.1",
-    "eslint": "^6.3.0",
+    "eslint": "^6.4.0",
     "eslint-config-simplabs": "^0.4.0",
     "eslint-plugin-ember": "^6.9.1",
     "eslint-plugin-qunit": "^4.0.0",

yarn.lock

@@ -3713,10 +3713,10 @@ eslint@^5.6.0:
     table "^5.2.3"
     text-table "^0.2.0"
 
-eslint@^6.3.0:
-  version "6.3.0"
-  resolved "https://registry.yarnpkg.com/eslint/-/eslint-6.3.0.tgz#1f1a902f67bfd4c354e7288b81e40654d927eb6a"
-  integrity sha512-ZvZTKaqDue+N8Y9g0kp6UPZtS4FSY3qARxBs7p4f0H0iof381XHduqVerFWtK8DPtKmemqbqCFENWSQgPR/Gow==
+eslint@^6.4.0:
+  version "6.4.0"
+  resolved "https://registry.yarnpkg.com/eslint/-/eslint-6.4.0.tgz#5aa9227c3fbe921982b2eda94ba0d7fae858611a"
+  integrity sha512-WTVEzK3lSFoXUovDHEbkJqCVPEPwbhCq4trDktNI6ygs7aO41d4cDT0JFAT5MivzZeVLWlg7vHL+bgrQv/t3vA==
   dependencies:
     "@babel/code-frame" "^7.0.0"
     ajv "^6.10.0"