Add vc-retrieve-tag-hook to mood-line--hooks-alist

This change should help mood-line to update displayed vs status
when branch is switched using vc-switch-branch

mood-line.el

@@ -732,7 +732,8 @@ Modal editing modes checked, in order:
         flycheck-status-changed-functions))
     (mood-line-segment-vc--update
      . (find-file-hook
-        after-save-hook)))
+        after-save-hook
+        vc-retrieve-tag-hook)))
   "Alist of update functions and their corresponding hooks.")
 
 (defconst mood-line--advice-alist