fix(package): update @angular/flex-layout to version 7.0.0-beta.19

Closes #311

Author: greenkeeper[bot]

package.json

@@ -34,7 +34,7 @@
     "@angular/common": "4.3.6",
     "@angular/compiler": "4.3.6",
     "@angular/core": "4.3.6",
-    "@angular/flex-layout": "2.0.0-beta.9",
+    "@angular/flex-layout": "7.0.0-beta.19",
     "@angular/forms": "4.3.6",
     "@angular/http": "4.3.6",
     "@angular/material": "2.0.0-beta.10",