Fix: files_upload_v2 with channel.

Author: dblock

CHANGELOG.md

@@ -1,5 +1,6 @@
 ### 2.5.2 (Next)
 
+* [#548](https://github.com/slack-ruby/slack-ruby-client/pull/548): Fix: `files_upload_v2` with `#channel` - [@dblock](https://github.com/dblock).
 * Your contribution here.
 
 ### 2.5.1 (2025/02/11)

lib/slack/web/api/helpers/files.rb

@@ -46,7 +46,7 @@ def files_upload_v2(params = {})
                 conversations_id(channel: channel)['channel']['id']
               end.uniq.join(',')
             elsif params[:channel]
-              complete_upload_request_params[:channel] = conversations_id(
+              complete_upload_request_params[:channel_id] = conversations_id(
                 channel: params[:channel]
               )['channel']['id']
             elsif params[:channel_id]