Upgrade stylelint from 14.8.1 to 14.9.1 (#192)

* New rule: `keyframe-block-no-duplicate-selectors`

Provide by upgrading stylelint-config-recommended from 7.0.0 to 8.0.0,
which we should have done before for compatibility with the versions
of stylelint we're using; whoops.

package.json

@@ -45,8 +45,8 @@
 		"browserslist-config-wikimedia": "0.4.0",
 		"postcss-less": "6.0.0",
 		"postcss-html": "1.5.0",
-		"stylelint": "14.8.1",
-		"stylelint-config-recommended": "7.0.0",
+		"stylelint": "14.9.1",
+		"stylelint-config-recommended": "8.0.0",
 		"stylelint-no-unsupported-browser-features": "5.0.3"
 	},
 	"peerDependencies": {

test/fixtures/default/invalid.css

@@ -169,6 +169,17 @@ span {
 	/* ... */
 }
 
+@keyframes foo {
+	/* stylelint-disable-next-line block-no-empty */
+	0% {
+
+	}
+	/* stylelint-disable-next-line keyframe-block-no-duplicate-selectors, block-no-empty */
+	0% {
+
+	}
+}
+
 .a .k {
 	/* stylelint-disable-next-line named-grid-areas-no-invalid */
 	grid-template-areas: '';