add r0 endpoint to PUT /_matrix/client/r0/room_keys/keys

there's no reason to be needlessly pessimistic, they are
functionally the same.

see https://github.com/element-hq/hydrogen-web/issues/741

Signed-off-by: strawberry <strawberry@puppygock.gay>

crates/ruma-client-api/src/backup/add_backup_keys.rs

@@ -23,6 +23,7 @@ pub mod v3 {
         authentication: AccessToken,
         history: {
             unstable => "/_matrix/client/unstable/room_keys/keys",
+            1.0 => "/_matrix/client/r0/room_keys/keys",
             1.1 => "/_matrix/client/v3/room_keys/keys",
         }
     };