Bump csstree to 1.1.3

Author: lahmatiy

package.json

@@ -6,7 +6,7 @@
         "highcharts": "^8.0.0",
         "@discoveryjs/discovery": "1.0.0-beta.61",
         "@discoveryjs/cli": "^2.0.0-beta.12",
-        "css-tree": "^1.1.2",
+        "css-tree": "^1.1.3",
         "diff": "^4.0.1",
         "eslint": "^7.0.0",
         "resolve": "^1.5.0"