fix(package): update @angular/cdk to version 6.4.0

Closes #319

Author: greenkeeper[bot]

package.json

@@ -30,7 +30,7 @@
   },
   "dependencies": {
     "@angular/animations": "4.3.6",
-    "@angular/cdk": "2.0.0-beta.10",
+    "@angular/cdk": "6.4.0",
     "@angular/common": "4.3.6",
     "@angular/compiler": "4.3.6",
     "@angular/core": "4.3.6",