Add install doctl script

dot_local/bin/executable_install-doctl

@@ -0,0 +1,20 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+# shellcheck disable=SC1091
+source "${XDG_DATA_HOME}/buddy-up/includes/utils.sh"
+
+APP=doctl
+VERSION=${VERSION:-1.98.1}
+DEST=${XDG_DATA_HOME}/apps/releases/${APP}
+
+main() (
+	URL=https://github.com/digitalocean/doctl/releases/download/v${VERSION}/doctl-${VERSION}-$(get_os)-$(get_arch).tar.gz
+
+	extract_tarball "${URL}" "${DEST}/${VERSION}"
+	set_current_link "${DEST}" "${VERSION}"
+	set_link "${XDG_BIN_HOME}/${APP}" "${DEST}" "${APP}"
+)
+
+main "${@}"