Bump NLog.Config from 4.7.6 to 4.7.7
Bumps [NLog.Config](https://github.com/NLog/NLog) from 4.7.6 to 4.7.7.
- [Release notes](https://github.com/NLog/NLog/releases)
- [Changelog](https://github.com/NLog/NLog/blob/dev/CHANGELOG.md)
- [Commits](https://github.com/NLog/NLog/commits)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>