Update .stylelint config from v4.

grunt/.stylelintrc

@@ -1,12 +1,12 @@
 {
-  "extends": ["stylelint-config-standard"],
+  "extends": [
+    "stylelint-config-standard"
+  ],
   "plugins": [
     "stylelint-order"
   ],
   "rules": {
-    "at-rule-empty-line-before": [null,
-      "except": ["first-nested"]
-    ],
+    "at-rule-empty-line-before": null,
     "at-rule-name-space-after": "always",
     "at-rule-no-vendor-prefix": true,
     "at-rule-semicolon-space-before": "never",
@@ -20,12 +20,27 @@
     "declaration-empty-line-before": null,
     "declaration-no-important": true,
     "font-family-name-quotes": "always-where-recommended",
-    "font-weight-notation": "numeric",
+    "font-weight-notation": [
+      "numeric",
+      {
+        "ignore": [
+          "relative"
+        ]
+      }
+    ],
     "function-url-no-scheme-relative": true,
     "function-url-quotes": "always",
     "length-zero-no-unit": true,
     "max-empty-lines": 2,
     "max-line-length": null,
+    "media-feature-name-no-unknown": [
+      true,
+      {
+        "ignoreMediaFeatureNames": [
+          "prefers-reduced-motion"
+        ]
+      }
+    ],
     "media-feature-name-no-vendor-prefix": true,
     "media-feature-parentheses-space-inside": "never",
     "media-feature-range-operator-space-after": "always",
@@ -263,6 +278,7 @@
     "selector-max-universal": 1,
     "selector-no-qualifying-type": true,
     "selector-no-vendor-prefix": true,
+    "shorthand-property-no-redundant-values": true,
     "string-quotes": "double",
     "value-keyword-case": "lower",
     "value-list-comma-newline-after": "never-multi-line",