Fix citation

Author: Raphael Meudec

CITATION.cff

@@ -2,13 +2,13 @@
 # Visit https://bit.ly/cffinit to generate yours today!
 
 cff-version: 1.2.0
-title: tf-explain, Interpretability Methods for tf.keras models with TensorFlow 2.x
+title: tf-explain
+abstract: Interpretability Methods for tf.keras models with TensorFlow 2.x
 version: 0.3.0
 date-released: 2021-02-04
-message: >-
-  If you use this software, please cite it using the
-  metadata from this file.
+message: "If you use tf-explain in your research, please cite it using these metadata."
 type: software
+repository-code: "https://github.com/sicara/tf-explain"
 authors:
   - given-names: Raphael
     family-names: Meudec