Support URL ending with /

[davidak]

[davidak@X230:~/code/cli/bin]$ CODIMD_SERVER='https://pad.nixnet.services/' ./codimd login --email *****@*****.de **********
parse error: Invalid numeric literal at line 1, column 10
Failed to login at https://pad.nixnet.services/.

It works when i remove the / like in the example.

Example:
    $ env CODIMD_SERVER='https://codimd.example.com' codimd import /path/to/your/content.md

Please support such URLs for better UX.

[pirate]

Fixed faf4b65