update contamination.csv

contamination_report.csv

@@ -707,3 +707,5 @@ zest;;EleutherAI/pile;;corpus;;;0.0;data-based;https://arxiv.org/abs/2310.20707;
 zest;;allenai/c4;;corpus;;;0.0;data-based;https://arxiv.org/abs/2310.20707;2
 zest;;oscar-corpus/OSCAR-2301;;corpus;;;0.0;data-based;https://arxiv.org/abs/2310.20707;2
 zest;;togethercomputer/RedPajama-Data-V2;;corpus;;;0.0;data-based;https://arxiv.org/abs/2310.20707;2
+
+cnn_dailymail;;allenai/c4;;corpus;;;0.0;data-based;https://arxiv.org/abs/2310.20707;