Fix ReadTheDocs build: specify linkify-it-py version

Author: muditbhargava66

docs/requirements.txt

@@ -33,3 +33,4 @@ scikit-learn>=1.3.0,<2.0.0
 scikit-image>=0.20.0,<1.0.0
 tqdm>=4.66.0,<5.0.0
 psutil>=5.9.0,<6.0.0
+linkify-it-py>=2.0.0