If this isn't changed in the package, you can still fork the package on your own repo, solve the issue and use your own forked version of the package in your flutter app this way :
dependencies:
some_package:
git:
url: https://github.com/your-username/the-package.git. // the package on your repo
ref: master # Or a specific branch/tag/commit
In the last version of flutter ( on the date of this document) bodytext1 has been deprecated and should use bodylarge instead. source : https://api.flutter.dev/flutter/material/TextTheme/bodyText1.html
If this isn't changed in the package, you can still fork the package on your own repo, solve the issue and use your own forked version of the package in your flutter app this way : dependencies: some_package: git: url: https://github.com/your-username/the-package.git. // the package on your repo ref: master # Or a specific branch/tag/commit