Add ability to update function description

Add ability to update function description I am not sure why it's not letting me update the description. I first got an error message: "Unexpected token 'S', 'Status: 40'... is not valid JSON," I then tried to debug it and got a different error. I am not sure at this point. I checked similar PRs. it could be a typo but I was unable to figure it out. Please advise @xx-db.  fixes #42