Update DOKKU_SCALE from Procfile during ps:scale

This is needed so that we report on processes added to an app's
Procfile.

plugins/ps/functions

@@ -194,7 +194,17 @@ ps_scale() {
   local DOKKU_PROCFILE="$DOKKU_ROOT/$APP/DOKKU_PROCFILE"
   shift 1
 
-  [[ ! -e $DOKKU_SCALE_FILE ]] && generate_scale_file "$APP" "$IMAGE_TAG" >/dev/null 2>&1
+  # shellcheck disable=SC2015
+  [[ ! -e $DOKKU_PROCFILE ]] && extract_procfile "$APP" "$IMAGE_TAG" >/dev/null 2>&1 || true
+  if [[ ! -e $DOKKU_SCALE_FILE ]] ; then
+    generate_scale_file "$APP" "$IMAGE_TAG" >/dev/null 2>&1
+  elif [[ -e $DOKKU_PROCFILE ]] ; then
+    for PROC_NAME in $(procfile-util list --procfile "$DOKKU_PROCFILE"); do
+      if ! grep -qE "^${PROC_NAME}=" "$DOKKU_SCALE_FILE"; then
+        echo "$PROC_NAME=0" >> "$DOKKU_SCALE_FILE"
+      fi
+    done
+  fi
   if [[ -z "$@" ]]; then
     dokku_log_info1_quiet "Scaling for $APP"
     dokku_col_log_msg_quiet "proctype" "qty"