Add a link to Barrak&Adams citation (#5592)

README.rst

@@ -222,7 +222,7 @@ Citation
 Iterative, *DVC: Data Version Control - Git for Data & Models* (2020)
 `DOI:10.5281/zenodo.012345 <https://doi.org/10.5281/zenodo.3677553>`_.
 
-Barrak, A., Eghan, E.E. and Adams, B. On the Co-evolution of ML Pipelines and Source Code - Empirical Study of DVC Projects, in Proceedings of the 28th IEEE International Conference on Software Analysis, Evolution, and Reengineering, SANER 2021. Hawaii, USA, to appear.
+Barrak, A., Eghan, E.E. and Adams, B. `On the Co-evolution of ML Pipelines and Source Code - Empirical Study of DVC Projects <https://mcis.cs.queensu.ca/publications/2021/saner.pdf>`_ , in Proceedings of the 28th IEEE International Conference on Software Analysis, Evolution, and Reengineering, SANER 2021. Hawaii, USA.
 
 
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