Features

• Added DNS lookup using Google DNS, refactored IP code (#246) @bee-san
• Take file of addresses as input (#237) @bee-san

Maintenance

• Refactored tests, introduced default function in test context for structs (#235) @bergabman
• Increase code coverage (#236) @bee-san
• Update Dockerfile to encourage layer caching (#241) @CMNatic
• docs: add dmitris as a contributor (#232) @allcontributors
• Bump structopt from 0.3.17 to 0.3.18 (#243) @dependabot-preview

Bugs

• Fix version tag typo in docker usage (#234) @CMNatic
• Update README for v1.9.0 release (#233) @CMNatic