Bump Gitaly version to 1.42.3

This change makes sure Gitaly includes a fix to make rebase work again
properly.

Part of: https://gitlab.com/gitlab-org/gitlab-ce/issues/62353

GITALY_SERVER_VERSION

-1.42.0
+1.42.3

app/models/repository.rb

@@ -1056,7 +1056,7 @@ class Repository
   end
 
   def rebase(user, merge_request)
-    if Feature.disabled?(:two_step_rebase, default_enabled: false)
+    if Feature.disabled?(:two_step_rebase, default_enabled: true)
       return rebase_deprecated(user, merge_request)
     end
 

changelogs/unreleased/dm-disable-two-step-rebase.yml

----
-title: Disable two-step rebase which could cause rebases to hang
-merge_request: 28778
-author:
-type: other

changelogs/unreleased/zj-gitlab-ce-zj-bump-gitaly.yml

+---
+title: Stop two-step rebase from hanging when errors occur
+merge_request: 29068
+author:
+type: fixed