chore: update stylelint version (#2268)

Update the version of stylelint to remove "Can not parse selector".

Author: belev

package.json

@@ -88,7 +88,7 @@
     "run-sequence": "^1.2.2",
     "sass": "^0.5.0",
     "strip-ansi": "^3.0.0",
-    "stylelint": "^7.5.0",
+    "stylelint": "^7.7.0",
     "symlink-or-copy": "^1.0.1",
     "travis-after-modes": "0.0.6-2",
     "ts-node": "^0.7.3",