`head` with negative byte/line counts is not portable

[kleinschmidt]

on macOS I get

➜ git config --get remote.origin.url | grep -o '[^:/]*$' | head -c-5
head: illegal byte count -- -5

when running this line

[kleinschmidt]

this is just removing the .git extension in the repo URL so we should use something portable like sed:

➜ git config --get remote.origin.url | grep -o '[^:/]*$' | sed 's/.git$//'
julia_pod

[kleinschmidt]

or

➜ git config --get remote.origin.url | xargs basename -s .git
julia_pod