Manifest repo url is blocked by firefox

[wrenger]

The repository url in the package.json contains a username, which causes problems in some browsers.

Jed/package.json

Line 8 in 351c47d

"url": "https://SlexAxton@github.com/SlexAxton/Jed.git"

By opening this link in firefox the browser attempts to login to github with the SlexAxton username and shows the following error:

You are about to log in to the site “github.com” with the username “SlexAxton”, but the website does not require authentication. This may be an attempt to trick you.

[wrenger]

The issue could be solved by changing the url to https://github.com/SlexAxton/Jed.git (or https://github.com/messageformat/Jed.git)