fix: force shell to be bash (#6)

If you are using something other than bash for your host shell (zsh for
example), which are not available on the build env, the shell will not
execute and the right pane is empty. To prevent this, the shell need to
be forced to bash.

This fixes #4

alpkg

@@ -45,6 +45,7 @@ create-pkg-script() {
   cat <<-'_EOF_' >"$CHROOT_DIR/$PACKAGE_DIR/pkg.sh"
 		#!/usr/bin/env bash
 		set -e
+    export SHELL=bash
 		pkg=""
 		lint_pkg=false
 		edit_pkg=true