The plugin repo started to fail pre-submit CIs on publish check after the 1.17 stable release. The plugin repo currently only runs the publish check on stable.

One example of such failure is https://cirrus-ci.com/task/5853319912488960
The log doesn't show any useful information other than a warning that previously wouldn't cause the pub publish check to fail.

I plan to fix it by update the lower bound of the dart dependency to 2.1.0 from 2.0.0-dev.28.0

@csells The firebase repo would probably hit the same issue.