!223 Upload paper sharing materials of dx sig on 2021-11-18

Merge pull request !223 from Guoqiang QI/paper_sharing

sigs/dx/paper/README.md

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+## Paper Share Notes
+
+### 2021-11-18
+
+- [What can OSS mailing lists tell us.](http://140.83.83.152:30036/s/TakFDocAgdAnbtr) --shared by Wang Yuhang
+- [An empirical study on using multi labels forIssues in github.](http://140.83.83.152:30036/s/p4YTbdr4aSCrb6Z) --shared by Cao Jie
+- [Magnet or sticky for measuring developer attraction and retention.](http://140.83.83.152:30036/s/tZsbrsTB7e3cG78) --shared by Chang Xiyu