Bugfix parse dhcp log header

[verovaleros]

Description

The dhcp.log contains a different header. Instead of uid contains uids. This caused the column not to be parsed properly and, therefore, to generate an empty labelled file.

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

• Run locally the zeek-files-labeler.py on a zeek folder
• Manually verified the output is correct

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings

[verovaleros]

I talked about the changes in-person with the assigned reviewer.