Fix 404 when IP input is missing

[UmanShahzad]

The library essentially queries https://ipinfo.io//geo when we call the function without an IP input, and this endpoint (with the 2 slashes before geo) gives a 404. Likely we changed this behavior in the API at some point so it broke the Perl SDK which didn't have this problem before.

Just a simple fix of not accidentally adding an extra slash is needed.