Merge pull request #4302 from szhorvat/patch-1

use igraph instead of python-igraph, as the latter name is deprecated for "pip install"

topics/single-cell/tutorials/scrna-case_JUPYTER-trajectories/tutorial.md

@@ -65,7 +65,7 @@ pip install scanpy
 pip install fa2
 ```
 ```python
-pip install python-igraph
+pip install igraph
 ```
 ```python
 pip install louvain