Merge branch 'winh-stylelint-valid-json' into 'master'

Make stylelint config a valid JSON file

See merge request gitlab-org/gitlab-ce!27721

.stylelintrc

@@ -2,7 +2,7 @@
    "plugins":[
       "./scripts/frontend/stylelint/stylelint-duplicate-selectors.js",
       "./scripts/frontend/stylelint/stylelint-utility-classes.js",
-      "stylelint-scss",
+      "stylelint-scss"
    ],
    "rules":{
       "at-rule-blacklist":[
@@ -94,7 +94,7 @@
          {
             "message":"Selector should be written in lowercase with hyphens (selector-class-pattern)",
             "severity": "warning"
-         },
+         }
       ],
       "selector-list-comma-newline-after":"always",
       "selector-max-compound-selectors":[3, { "severity": "warning" }],
@@ -104,8 +104,8 @@
       "selector-pseudo-element-no-unknown":true,
       "shorthand-property-no-redundant-values":true,
       "string-quotes":"single",
-      "value-no-vendor-prefix":[true, { ignoreValues: ["sticky"] }],
+      "value-no-vendor-prefix":[true, { "ignoreValues": ["sticky"] }],
       "stylelint-gitlab/duplicate-selectors":[true,{ "severity": "warning" }],
-      "stylelint-gitlab/utility-classes":[true,{ "severity": "warning" }],
+      "stylelint-gitlab/utility-classes":[true,{ "severity": "warning" }]
    }
 }