config: disable user-facing version Azure SEV SNP fetch for v2.8 (#1882)

* config: disable user-facing version fetch for Azure SEV SNP

don't allow "latest" value and disable user-facing version fetcher for Azure SEV SNP

Co-authored-by: @derpsteb

* fix unittests

* attestation: getTrustedKey

---------

Co-authored-by: Otto Bittner <cobittner@posteo.net>

internal/config/attestationversion_test.go

@@ -9,6 +9,7 @@ package config
 import (
 	"testing"
 
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"gopkg.in/yaml.v3"
 )
@@ -44,3 +45,39 @@ func TestVersionMarshalYAML(t *testing.T) {
 		})
 	}
 }
+
+func TestVersionUnmarshalYAML(t *testing.T) {
+	tests := []struct {
+		name      string
+		expected  AttestationVersion
+		yamlInput string
+		wantErr   bool
+	}{
+		// TODO(elchead): activate latest logic for next release AB#3036
+		{
+			name:      "latest value is not allowed",
+			expected:  AttestationVersion{},
+			yamlInput: "latest\n",
+			wantErr:   true,
+		},
+		{
+			name: "value 5 resolves to 5",
+			expected: AttestationVersion{
+				Value: 5,
+			},
+			yamlInput: "5\n",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			sut := AttestationVersion{}
+			err := yaml.Unmarshal([]byte(tt.yamlInput), &sut)
+			if tt.wantErr {
+				assert.Error(t, err)
+				return
+			}
+			assert.NoError(t, err)
+			assert.Equal(t, tt.expected.IsLatest, sut.IsLatest)
+		})
+	}
+}