Improve latest version error message

[JackBurdick]

No worries if you don't want to include. Please double-check on your end.

This was my first time using a release and this error message could have saved me a bit of time.

NOTE: I was surprised to find that if I used latest_release.json()['tag_name'] twice in the same block I received an error (which is why gh_json = latest_release.json() exists). I then changed file_list_json = file_list.json() in _download_all_files to match -- but will take out if desired.

I (my fixer) also removed a couple extra spaces at the end of lines and I decided to include

[rdehuyss]

Thx for this! I will soon have a look, test it and merge it then!