* Generated code now ignores the `avoid_escaping_inner_quotes` lint in
  case `String` literals need inner quotes.
* Adjusted tests to now compare against checked-in files instead of
  against in-memory files generated by the tests.
* Use `currentDartFilePath` from `package:dartbag` instead of parsing
  the stack trace ourselves.
* Updated dependencies.
* Require Dart 2.19.
* Add a (GNU) makefile.