Right now some packages have intentional dart pub publish --dry-run warnings. firehose fails the build on the dry-run checks; we may want some additional configurability here. See dart-lang/test#1923 for context.

Some ideas are:

• for pub publish dry-run to support some ignore: xxx syntax in pubspec files
• have a way for a repo to configure that dry run checks shouldn't be run for specific packages
• have a way for firehose to distinguish dry-run warnings vs errors and not fail builds for warnings (as pub is currently, any warnings sets an exit code of 65)