Change the filename from lowercase 'version' to uppercase 'VERSION'.

The lowercase 'version' causes a warning

`cat: /home/ly/workspace/buildpack-python/buildpack-packager/lib/../../VERSION: No such file or directory`

and  the created online/offline package name with blank version, i.e. "python_buildpack-v.zip", the correct name should be "python_buildpack-v1.0.1.zip".