Bump handlebars from 4.4.5 to 4.7.7 in /src (DanWahlin#10)

Author: dependabot[bot]

src/package-lock.json

@@ -31,7 +31,7 @@
         "errorhandler": "^1.5.0",
         "express": "^4.16.2",
         "express-handlebars": "^3.0.0",
-        "handlebars": "^4.4.5",
+        "handlebars": "^4.7.7",
         "handlebars-helpers": "^0.10.0",
         "handlebars-layouts": "^3.1.4",
         "express-session": "^1.15.6",