Update shebang to use env bash.
Update shebang to use env bash.

* For me, this is bash 4.x

sjdweb/mac-bootstrap,joshukraine/mac-bootstrap,tadelv/mac-bootstrap,joshukraine/mac-bootstrap,tadelv/mac-bootstrap,sjdweb/mac-bootstrap,tadelv/mac-bootstrap,joshukraine/mac-bootstrap