[gnome-builder] build: fix typo

[Christian Hergert <chergert src gnome org>]

commit a1c40c0c9da73ece159c2f5b0eeeb15516677cb3
Author: Christian Hergert <chergert redhat com>
Date:   Fri Sep 3 10:35:27 2021 -0700

    build: fix typo

 .gitlab-ci.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 318a3e710..046934267 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -13,7 +13,7 @@ flatpak:
     APP_ID: "org.gnome.Builder"
     BUNDLE: "gnome-builder-git.flatpak"
   before_script:
-    - flatpak --user remote --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
+    - flatpak --user remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
     - flatpak --user install -y flathub org.freedesktop.Sdk.Extension.llvm12//21.08
 
 nightly: