Fix LEAPP_IPU_IN_PROGRESS (9to1 -> 9to10)

Implementation of processing versions inside commands/command_utils.py
has been bugy. One of function returned string instread of list
which led to the situation that only the first character has been
returned instead of the first chunk. This has been ok for releases
where major version is just one decimal. However since el 10 it has
been buggy and generated set envar:
    LEAPP_IPU_IN_PROGRESS=9to1
instead of
    LEAPP_IPU_IN_PROGRESS=9to10

Now it should be working correctly again.

jira: OAMG-11260

commands/command_utils.py

@@ -26,7 +26,7 @@ def check_version(version):
     """
     if not re.match(VERSION_REGEX, version):
         raise CommandError('Unexpected format of target version: {}'.format(version))
-    return version.split('.')[0]
+    return version.split('.')
 
 
 def get_major_version(version):