fix(demo): set angular material to v7.3.7

Author: AnthonyNahas

demo/package.json

@@ -29,14 +29,14 @@
   "dependencies": {
     "@angular-material-extensions/pages": "^2.1.0",
     "@angular/animations": "7.2.12",
-    "@angular/cdk": "^7.3.6",
+    "@angular/cdk": "^7.3.7",
     "@angular/common": "7.2.12",
     "@angular/compiler": "7.2.12",
     "@angular/core": "7.2.12",
     "@angular/flex-layout": "^7.0.0-beta.24",
     "@angular/forms": "7.2.12",
     "@angular/http": "7.2.12",
-    "@angular/material": "^7.3.6",
+    "@angular/material": "^7.3.7",
     "@angular/platform-browser": "7.2.12",
     "@angular/platform-browser-dynamic": "7.2.12",
     "@angular/platform-server": "7.2.12",