fix(package): update @angular/material to version 9.2.3

Closes #34

Author: greenkeeper[bot]

package.json

@@ -41,7 +41,7 @@
     "@angular/core": "^7.2.11",
     "@angular/flex-layout": "^7.0.0-beta.24",
     "@angular/forms": "^7.2.11",
-    "@angular/material": "^7.3.6"
+    "@angular/material": "^9.2.3"
   },
   "devDependencies": {
     "@angular-devkit/schematics": "^7.3.7",