Update README.md with zenodo badge (#216)

README.md

@@ -4,6 +4,7 @@
 [![Build Status](https://github.com/scikit-adaptation/skada/actions/workflows/testing.yml/badge.svg)](https://github.com/scikit-adaptation/skada/actions)
 [![Codecov Status](https://codecov.io/gh/scikit-adaptation/skada/branch/main/graph/badge.svg)](https://codecov.io/gh/scikit-adaptation/skada)
 [![License](https://img.shields.io/badge/License-BSD_3--Clause-blue.svg)](https://opensource.org/licenses/BSD-3-Clause)
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 > [!WARNING]
 > This library is currently in a phase of active development. All features are subject to change without prior notice. If you are interested in collaborating, please feel free to reach out by opening an issue or starting a discussion.
@@ -226,4 +227,4 @@ The library is distributed under the 3-Clause BSD license.
 
 [27] S. Si, D. Tao and B. Geng. In IEEE Transactions on Knowledge and Data Engineering, (2010) [Bregman Divergence-Based Regularization for Transfer Subspace Learning](https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=4118b4fc7d61068b9b448fd499876d139baeec81)
 
-[28] Solomon, J., Rustamov, R., Guibas, L., & Butscher, A. (2014, January). [Wasserstein propagation for semi-supervised learning](https://proceedings.mlr.press/v32/solomon14.pdf). In International Conference on Machine Learning (pp. 306-314). PMLR.
+[28] Solomon, J., Rustamov, R., Guibas, L., & Butscher, A. (2014, January). [Wasserstein propagation for semi-supervised learning](https://proceedings.mlr.press/v32/solomon14.pdf). In International Conference on Machine Learning (pp. 306-314). PMLR.