Make sure apk doesn't go into interactive mode (MR 11)

Recent versions of postmarketOS configure apk to ask for confirmation
(empty /etc/apk/interactive file). Make sure we always run it
non-interactively in that script for better usability, we already ask
once for confirmation before doing anything.

upgrade.sh

@@ -39,6 +39,16 @@ UPGRADE_SCRIPT_LAST_MODIFIED="$(stat -c "%Y" "$0")"
 
 VERB="upgrade"
 
+# Wrap apk to never go into interactive mode. In postmarketOS, we configure apk
+# with /etc/apk/interactive to go into interactive mode by default, but this
+# would give bad usability here. The user already has to confirm once at the
+# start of the script. Use </dev/null because --no-interactive is not available
+# in all apk versions.
+_APK="$(command -v apk)"
+apk() {
+	"$_APK" "$@" </dev/null
+}
+
 set_colors() {
 	# See https://no-color.org
 	if [ -n "$NO_COLOR" ]; then