[fractal] docs: Update README because of changes in milestones

[Kévin Commaille <kcommaille src gnome org>]

commit 2810e2f10da5fae667de2baf56577110044ae114
Author: Kévin Commaille <zecakeh tedomum fr>
Date:   Fri Jul 29 11:52:26 2022 +0200

    docs: Update README because of changes in milestones

 README.md | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)
---
diff --git a/README.md b/README.md
index a770dda12..dae4e5598 100644
--- a/README.md
+++ b/README.md
@@ -24,8 +24,7 @@ This effort was called Fractal Next.
 
 Fractal Next now replaced our previous codebase, and has become the new nightly version. It isn't
 yet ready for a release and you can follow along our progress towards it by looking at the
-[feature parity](https://gitlab.gnome.org/GNOME/fractal/-/milestones/18) and
-[Fractal v5 (fractal-next)](https://gitlab.gnome.org/GNOME/fractal/-/milestones/21) milestones.
+[Fractal v5 (Fractal-next)](https://gitlab.gnome.org/GNOME/fractal/-/milestones/18) milestone.
 
 ## Installation instructions