Bump NETStandard.Library from 1.6.1 to 2.0.3
Bump NETStandard.Library from 1.6.1 to 2.0.3

Bumps [NETStandard.Library](https://github.com/dotnet/standard) from 1.6.1 to 2.0.3.
- [Release notes](https://github.com/dotnet/standard/releases)
- [Commits](https://github.com/dotnet/standard/commits/v2.0.3)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
FatturaElettronicaPA/FatturaElettronicaPA.Forms