change python version

README.md

@@ -26,8 +26,7 @@ It includes a fully-automated coassembly step informed by optimal clustering of
 A working installation of **conda** and **git** is mandatory to build magneto. If you have **mamba** already install on your system, the creation of the main environment will be faster.
 
 
-- python 3.7+
-- python 2.7
+- python 3.8+
 - snakemake 6.3.0
 - mamba 1.5.8
 - conda 4.10.3