Updated Bootstrap to 4.3.1 to fix security issues

Author: jmanuelcorral

src/Web/WebSPA/package-lock.json

@@ -39,7 +39,7 @@
     "@angular/router": "^7.2.10",
     "@aspnet/signalr": "1.0.3",
     "@ng-bootstrap/ng-bootstrap": "3.3.0",
-    "bootstrap": "4.1.3",
+    "bootstrap": "4.3.1",
     "core-js": "^2.5.0",
     "file-loader": "2.0.0",
     "font-awesome": "4.7.0",