[ci] Display size of uploaded regression report

Dangerfile

@@ -37,6 +37,8 @@ def upload_report
     end
 
     `tar -cf #{tar_filename} diff/`
+    tar_size = (10 * File.size(tar_filename) / 1024 / 1024)/10.0
+    @logger.info "Uploading file #{tar_filename} (#{tar_size}mb) now..."
     report_url = `curl -u #{ENV['PMD_CI_CHUNK_TOKEN']} -T #{tar_filename} https://chunk.io`
     if $?.success?
       @logger.info "Successfully uploaded #{tar_filename} to #{report_url}"