Unsigned SAML LogoutRequest Acceptance in gosaml2

Summary The ValidateEncodedLogoutRequestPOST function in gosaml2 accepts completely unsigned SAML LogoutRequest messages even when SkipSignatureValidation is set to false. When validateElementSignature returns dsig.ErrMissingSignature, the code in decodelogoutrequest.go:60-62 silently falls throu...