[tepl] docs: roadmap-done: change "5.2" to "6.0"

[Sébastien Wilmet <swilmet src gnome org>]

commit 56991dc451b3cc25144456ba3a3afafd4a3d8285
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Mon Nov 9 22:48:24 2020 +0100

    docs: roadmap-done: change "5.2" to "6.0"

 docs/roadmap-done.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/docs/roadmap-done.md b/docs/roadmap-done.md
index 4b79007..c47b026 100644
--- a/docs/roadmap-done.md
+++ b/docs/roadmap-done.md
@@ -1,7 +1,7 @@
 Tepl roadmap - done tasks
 =========================
 
-New small features in Tepl 5.2 (GNOME 40)
+New small features in Tepl 6.0 (GNOME 40)
 -----------------------------------------
 
 - TeplSpaceDrawerPrefs: preferences widget for GtkSourceSpaceDrawer.