Set no-unsupported-browser-features severity to warning

Author: Aaron Imming

.stylelintrc

@@ -50,7 +50,7 @@
     "number-no-trailing-zeros"                         : true,
     "property-case"                                    : "lower",
     "plugin/no-unsupported-browser-features"           : [true, {
-      "severity": "error",
+      "severity": "warning",
       "ignore": ["calc", "user-select-none", "multicolumn", "css-appearance", "border-radius", "pointer"]
     }],
     "rule-empty-line-before"                           : ["always", { "ignore": ["after-comment"], "except": ["inside-block-and-after-rule", "first-nested"] }],