chore: bump material version (angular#491)

Author: mmalerba

package.json

@@ -20,14 +20,14 @@
   "private": true,
   "dependencies": {
     "@angular/animations": "^6.0.9",
-    "@angular/cdk": "^6.4.1",
+    "@angular/cdk": "^6.4.2",
     "@angular/common": "^6.0.9",
     "@angular/compiler": "^6.0.9",
     "@angular/core": "^6.0.9",
     "@angular/forms": "^6.0.9",
     "@angular/http": "^6.0.9",
-    "@angular/material": "^6.4.1",
-    "@angular/material-moment-adapter": "^6.4.1",
+    "@angular/material": "^6.4.2",
+    "@angular/material-moment-adapter": "^6.4.2",
     "@angular/platform-browser": "^6.0.9",
     "@angular/platform-browser-dynamic": "^6.0.9",
     "@angular/router": "^6.0.9",