Bump Microsoft.Data.SqlClient in /tests/NLog.UnitTests
Bump Microsoft.Data.SqlClient in /tests/NLog.UnitTests

Bumps [Microsoft.Data.SqlClient](https://github.com/dotnet/sqlclient) from 2.1.2 to 2.1.3.
- [Release notes](https://github.com/dotnet/sqlclient/releases)
- [Changelog](https://github.com/dotnet/SqlClient/blob/main/CHANGELOG.md)
- [Commits](https://github.com/dotnet/sqlclient/compare/v2.1.2...v2.1.3)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
snakefoot/NLog,304NotModified/NLog,NLog/NLog