Fixed logger file read error on first run

[Solidsilver]

Following the instructions on a clean install of neovim, it failed on first run since ~/.config/nvim/ didn't exist. I added an init block to the logger so it would create this directory if it doesn't exist. I also made logger open function more verbose if it fails to open dep.log file

Note, even if you would rather this plugin not auto-create the directory, I think having an assert (or maybe some error logging) on the file open would still be good so users can see why it failed.