(🎁) Refactor project dependency configuration to use a lock file #15521
Description
I have witnessed many times when the CI has failed in master due to dependencies changing, these failures have always introduced additional work upon the maintainers.
I can suggest adopting a build tool such as Poetry, which provides very comprehensive management of project dependencies. From experience I can say that tools such as this can completely avoid the issues that I have observed within the mypy project.