support timezone: 0.9.0

[IVLIVS-III]

Issue description

The timezone dependency is available in version 0.9.0 but cannot be used in projects that depend on device_calendar: 4.2.0 because device_calendar depends on timezone: ^0.8.0.
Due to timezone being a 0.x.x version, automatic version solving is treating the change in minor version number as a "breaking change" that is not allowed automatically.

Steps to resolve this issue

• ensure device_calendar is compatible with timezone: 0.9.0. Compatibility should be given as long as device_calendar does not depend on named database files in package:timezone/data (for example, package:timezone/data/2021e.tzf), since the removal of those named files was the only breaking change from timezone: 0.8.x to 0.9.0.
• update the timezone dependency in pubspec.yaml to timezone: ^0.9.0

[vixez]

I created a fork here meanwhile with a version bump. As I needed it for other packages

  device_calendar:
    git:
      url: https://github.com/vixez/device_calendar.git
      ref: develop

[thomassth]

Give me a PR and I'll push it through

I can't self push without other maintainers' approval, which all seems to be inactive.

[IVLIVS-III]

@thomassth PR has been created, thx for your efforts in keeping this plugin alive.