middlewares.py

# Make sure to add the proxy address, username and passowrd 
# Make sure to append the ProxyMiddleware class to the DOWNLOADER_MIDDLEWARES dict in the settings.py file

from w3lib.http import basic_auth_header

class ProxyMiddleware:
  def process_request(self, request, spider):
      request.meta['proxy'] = "COMPANY PROXY URL OR ADDRESS"
      request.headers['Proxy-Authorization'] = basic_auth_header('USERNAME', 'PASSWORD')