CORS spec missing AllowOrigins field

[sergiofteixeira]

when using flagger crd to create virtualservice with allowOrigins, the crd will skip the line and in the final virtualService there is no allowOrigins line.

    corsPolicy:
      allowOrigins:
      - exact: "https://foo.com"
      allowCredentials: true

tested with this example.

a little bit critical, since istio 1.6 you have to use allowOrigins instead of origin.