Escape backslashes in cpplint.py
Escape backslashes in cpplint.py

This gets rid of DeprecationWarning on Windows.

Signed-off-by: Chris Lalancette <281cd07d7578d97c83271fbbf2faddb83ab3791c@openrobotics.org>

ament/ament_lint,ament/ament_lint,ament/ament_lint