runtime(zip): zip plugin does not work with Vim 9.0

Problem:  zip plugin does not work with Vim 9.0
          because of :defer
Solution: raise minimum Vim version to Vim 9.1

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/autoload/zip.vim b/runtime/autoload/zip.vim
index 148e45b..31fb327 100644
--- a/runtime/autoload/zip.vim
+++ b/runtime/autoload/zip.vim
@@ -68,8 +68,9 @@
   echohl Normal
 endfun
 
-if v:version < 900
- call s:Mess('WarningMsg', "***warning*** this version of zip needs vim 9.0 or later")
+if v:version < 901
+ " required for defer
+ call s:Mess('WarningMsg', "***warning*** this version of zip needs vim 9.1 or later")
  finish
 endif
 if !dist#vim#IsSafeExecutable('zip', g:zip_unzipcmd)