feat(@schematics/angular): update new workspaces to use Karma 6.3

Author: alan-agius4

packages/schematics/angular/workspace/files/package.json.template

@@ -30,7 +30,7 @@
     "@types/node": "^12.11.1",<% if (!minimal) { %>
     "jasmine-core": "~3.7.0",
     "jasmine-spec-reporter": "~6.0.0",
-    "karma": "~6.2.0",
+    "karma": "~6.3.0",
     "karma-chrome-launcher": "~3.1.0",
     "karma-coverage": "~2.0.3",
     "karma-jasmine": "~4.0.0",