Update ember-cli-stylelint to version 0.6.0 🚀 (#641)

* chore(package): update ember-cli-stylelint to version 0.6.0

https://greenkeeper.io/

* Fixed build/test warnings due to stylelint upgrading to 7.x

* Specifically use stylelint ^7.0.3

.stylelintrc

@@ -2,14 +2,10 @@
   "extends": "stylelint-config-concentric",
   "plugins": [
   "stylelint-declaration-use-variable",
-  "stylelint-value-border-zero",
   "stylelint-scss"
 ],
   "rules":{
     "sh-waqar/declaration-use-variable": "color",
-    "value-border-zero": {
-      "convention": "0"
-    },
     "scss/at-import-no-partial-extension": true,
     "scss/at-import-no-partial-leading-underscore": true,
     "scss/at-extend-no-missing-placeholder": true,
@@ -25,7 +21,7 @@
     "block-opening-brace-space-before": "always",
     "block-opening-brace-newline-after": "always-multi-line",
     "block-opening-brace-space-after": "always-single-line",
-    "no-missing-eof-newline": true,
+    "no-missing-end-of-source-newline": true,
     "no-duplicate-selectors": true,
     "no-eol-whitespace": true,
     "selector-max-compound-selectors": 4,
@@ -42,10 +38,10 @@
     "declaration-block-trailing-semicolon": "always",
     "function-comma-space-after": "never-single-line",
     "function-parentheses-space-inside": "never",
-    "function-url-quotes": "single",
+    "function-url-quotes": "always",
     "number-leading-zero": "never",
     "number-no-trailing-zeros": true,
-    "number-zero-length-no-unit": true,
+    "length-zero-no-unit": true,
     "rule-nested-empty-line-before": ["always-multi-line", {
       "ignore": ["after-comment"],
       "except": ["first-nested"]
@@ -55,6 +51,9 @@
     } ],
     "max-nesting-depth": 4,
     "shorthand-property-no-redundant-values": true,
-    "string-quotes": "single"
+    "string-quotes": "single",
+    "declaration-property-value-blacklist": {
+      "/^border/": ["none"]
+    }
   }
 }

package.json

@@ -53,7 +53,7 @@
     "ember-cli-release": "^0.2.9",
     "ember-cli-sass": "^5.2.1",
     "ember-cli-sri": "^2.1.0",
-    "ember-cli-stylelint": "^0.5.0",
+    "ember-cli-stylelint": "^0.6.0",
     "ember-cli-template-lint": "0.4.12",
     "ember-cli-test-loader": "^1.1.0",
     "ember-cli-uglify": "^1.2.0",
@@ -78,10 +78,10 @@
     "nano": "6.2.0",
     "pouchdb-list": "^1.1.0",
     "request": "2.74.0",
-    "stylelint-config-concentric": "1.0.3",
+    "stylelint": "^7.0.3",
+    "stylelint-config-concentric": "1.0.5",
     "stylelint-declaration-use-variable": "^1.4.0",
-    "stylelint-scss": "1.2.1",
-    "stylelint-value-border-zero": "^1.0.2"
+    "stylelint-scss": "1.3.4"
   },
   "ember-addon": {
     "paths": [