4.18.7 - Update UC Mode and add methods for verifying downloads via regex

Update UC Mode and add methods for verifying downloads via regex

• Make improvements to UC Mode
  --> This resolves #2112
  --> This resolves #2114
• Add methods for verifying downloads via regex
  --> This resolves #2113
  --> New method: self.is_downloaded_file_regex_present(regex)
  --> New method: self.assert_downloaded_file_regex(regex, timeout=None)
• Refresh optional Python dependencies

What's Changed

• Update UC Mode and add methods for verifying downloads via regex by @mdmintz in #2115

Full Changelog: v4.18.6...v4.18.7