Failing test with a negative UTC offset

[austindrenski]

I'm trying to build the test suite in UTC-5:00, and I think there's a timezone formatting issue here:

https://github.com/npgsql/Npgsql.EntityFrameworkCore.PostgreSQL/blob/713b79c9dac7b60273c7de4b0ae6b1fa997aa4a9/test/EFCore.PG.Tests/Storage/NpgsqlTypeMappingTest.cs#L37-L53

Swapping L46-L49 with the following fixed it on my dev machine:

var offset = TimeZoneInfo.Local.BaseUtcOffset.Hours;
Assert.StartsWith($"TIMESTAMPTZ '1997-12-17 07:37:16{offset:+00;-00}",
 mapping.GenerateSqlLiteral(new DateTime(1997, 12, 17, 7, 37, 16, DateTimeKind.Local)));

[austindrenski]

Addressed by 98970aa