Added open store method and force app version field

[2shrestha22]

Some user (including me) may want to open store link manually without needing to show dialog, similar to the advanced example where user manually open dialog.

OutlinedButton.icon(
  style: OutlinedButton.styleFrom(
    primary: AppColor.scaffoldBackground,
    side: const BorderSide(
      color: AppColor.scaffoldBackground,
    ),
  ),
  onPressed: () {
    //update app
    _newVersion.openStore(versionStatus);
  },
  icon: const Icon(Icons.cloud_download_outlined),
  label: const Text('Update now'), // TODO: translation
);

Also I have added forceAppVersion field so we can test by manually setting store app version.

final _newVersion = NewVersion(forceAppVersion: '2.2.3');

[timtraversy]

Thanks! I like both these changes a lot. My only thought is that the plugin now has _launchAppStore and openStore functions. I want to either combine those or name them more clearly.

[2shrestha22]

Sure, I will change them as needed.

[2shrestha22]

@timtraversy I have changed it as needed. Please have a look. Sorry for delay.
edit: I forgot to make launchAppStore() take VersionStatus but I think appStoreLink is also fine. What do you think?

[timtraversy]

OK, LGTM