Update clean-css

package-lock.json

@@ -557,13 +557,20 @@
       }
     },
     "clean-css": {
-      "version": "3.4.28",
-      "resolved": "https://registry.npmjs.org/clean-css/-/clean-css-3.4.28.tgz",
-      "integrity": "sha1-vxlF6C/ICPVWlebd6uwBQA79A/8=",
+      "version": "4.1.11",
+      "resolved": "https://registry.npmjs.org/clean-css/-/clean-css-4.1.11.tgz",
+      "integrity": "sha1-Ls3xRaujj1R0DybO/Q/z4D4SXWo=",
       "dev": true,
       "requires": {
-        "commander": "2.8.1",
-        "source-map": "0.4.4"
+        "source-map": "0.5.7"
+      },
+      "dependencies": {
+        "source-map": {
+          "version": "0.5.7",
+          "resolved": "https://registry.npmjs.org/source-map/-/source-map-0.5.7.tgz",
+          "integrity": "sha1-igOdLRAh0i0eoUyA2OpGi6LvP8w=",
+          "dev": true
+        }
       }
     },
     "cliui": {
@@ -636,15 +643,6 @@
         "delayed-stream": "1.0.0"
       }
     },
-    "commander": {
-      "version": "2.8.1",
-      "resolved": "https://registry.npmjs.org/commander/-/commander-2.8.1.tgz",
-      "integrity": "sha1-Br42f+v9oMMwqh4qBy09yXYkJdQ=",
-      "dev": true,
-      "requires": {
-        "graceful-readlink": "1.0.1"
-      }
-    },
     "component-emitter": {
       "version": "1.2.1",
       "resolved": "https://registry.npmjs.org/component-emitter/-/component-emitter-1.2.1.tgz",

package.json

@@ -17,7 +17,7 @@
     "url": "https://github.com/Microsoft/monaco-editor"
   },
   "devDependencies": {
-    "clean-css": "^3.4.20",
+    "clean-css": "^4.1.11",
     "event-stream": "^3.3.2",
     "gulp": "^3.9.1",
     "gulp-typedoc": "^2.0.0",