Promise support for only the latest compatible versions of file

[sidrao2006]

Follow up of #301

:sparkles: What kind of change does this PR introduce? (Bug fix, feature, docs update...)

Dependency version constraints update

:boom: Does this PR introduce a breaking change?

No

:bug: Recommendations for testing

N/A

:memo: Links to relevant issues/docs

N/A

:thinking: Checklist before submitting

• [x] All projects build
• [x] Follows style guide lines (code style guide)
• [x] Relevant documentation was updated
• [x] Rebased onto current develop

[renefloor]

Thanks for the idea, but it is better to support everything up to, but not including 7.0.0 (as your previous PR). Otherwise we need to update this package every time the dependency adds a bug fix or a new feature. The point of semantic versioning is that the dependency should not break anything without raising the major version, so we should be fine as long as the 'file' doesn't move to 7.0.0.

[sidrao2006]

@renefloor would it make sense to define such constraints for all direct dependencies? Currently, many users are facing dependency incompatibilities

[renefloor]

What do you mean? All dependencies are defined like this, that's what ^ does. for example

  http: ^0.13.0 -> this means >=0.13.0 <0.14.0
  image: ^3.0.1 -> this means >=3.0.1 <4.0.0

Many packages have recently raised a major version due to null safety, so that's why there are many incompatibilities. If you have problems with a specific package that could be fixed with different constraints please let me know. However, this package raised their dependencies as we want all dependencies to be migrated to null safety.