Update python version in docs.

Author: hunghaoti

docs/source/install.rst

@@ -24,7 +24,7 @@ In the following we show how to install Cytnx with conda.
 .. Note::
 
     1. We do not support a native Windows package at this stage. If you are using Windows OS, please use WSL.
-    2. [0.9] Currently, the supported Python versions are updated to: linux --  3.8/3.9/3.10; MacOS-osx64 -- 3.7+ (no conda support). You can change the python=* argument to the version you like.
+    2. Currently, the supported Python versions are updated to: linux --  3.9+; MacOS-osx64 -- 3.9+ (no conda support). You can change the python=* argument to the version you like.
 
 
 * For MacOS: