Bump System.Net.Http in /BoletoSimplesApiClient.UnitTests
Bump System.Net.Http in /BoletoSimplesApiClient.UnitTests

Bumps System.Net.Http from 4.3.1 to 4.3.4.

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>
BoletoSimples/boletosimples-csharp