change _pfile to _pFile in writeScoreCode function

[nikkhil13]

Describe the issue
As part of testing the import of python model using pzmm in SAS Model Manager on Viya 3.5, I encountered a "NameError" saying "_pfile" not found. After renaming it to "_pFile" and using the "Generate DS2 code" button, the error was resolved.

Version
1.6.0

[smlindauer]

I committed a fix to this problem. I will close this issue next time sasctl is pushed to PyPI.