docs: Switch shebang to bash since popd and pushd are bashisms
popd and pushed are not implemented in all shells
https://rgeissert.blogspot.com/2013/02/a-bashism-week-pushing-and-poping.html
popd and pushed are not implemented in all shells
https://rgeissert.blogspot.com/2013/02/a-bashism-week-pushing-and-poping.html