changelog-v2: mark upgrade action as changelog only

We don't need to recompute the others revlog to add the changelog-v2 feature.

This does not have much effect in practice as the `copies-sdc` upgrade still
triggers the other revlogs. This will be fixed in the next changeset.

mercurial/upgrade_utils/actions.py

@@ -380,6 +380,9 b' class changelogv2(requirementformatvaria'
     description = _(b'An iteration of the revlog focussed on changelog needs.')
     upgrademessage = _(b'quite experimental')
 
+    touches_filelogs = False
+    touches_manifests = False
+
 
 @registerformatvariant
 class removecldeltachain(formatvariant):