trim keys to 8 chars for matching with apt-key list (fix for #100)

:sparkles: hello partypuppets! :sparkles: 

this is a fix for #100. Please see this PR for all the info.
please let me know what i can do further to get this merged quickly.

thanks! :sparkling_heart: :smiley_cat: 

ben

PS: sorry for the unintentional scrambling of the commit message with emojis!
PPS: /cc @eodabas