Fix: TypeError: jwt is not a function

[luisjunco]

Problem: running the project with npm run dev gives the following error: TypeError: jwt is not a function.

Reason: in it's latest version, "express-jwt" has changed what it exports (we're using a syntax compatible with 7.x but in package.json we're still using v.6.x).

Solution: using "express-jwt" v.7.x will solve the issue.