Brief description of your issue

If you use YAMLs for the manifest and use UTF-8 with BOM, the first line is completely ignored. The first line usually holds the schema header. This might be a problem for a long time, but headers are checked now and if you use UTF-8 with BOM, the checks will fail.
Currently UTF-8 with BOM only works, if you place the schema header in the second line, leaving the first line blank. Or using UTF-8 without BOM.

Steps to reproduce

Use a YAML with UTF-8 with BOM, place the schema-header in the first line and run the validate

Expected behavior

The obe described usage should work

Actual behavior

The first line is ignored

Environment

Windows-Paket-Manager (Vorschau) v1.11.320-preview
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Windows: Windows.Desktop v10.0.26100.4061
Systemarchitektur: X64
Paket: Microsoft.DesktopAppInstaller v1.26.320.0

The current azure tests will fail also!