Remove mention of Python 2.x

Author: ricardoV94

pytensor/utils.py

@@ -38,7 +38,6 @@
 
 Note that according to Python documentation, `platform.architecture()` is
 not reliable on OS X with universal binaries.
-Also, sys.maxsize does not exist in Python < 2.6.
 'P' denotes a void*, and the size is expressed in bytes.
 """