yml: remove KES v0.13.5 and v0.14.0 config migration (#260)

This commit removes the already deprecated configuration
formats for KES <= v0.14.0.

Now, the KES server no longer supports config files
written before KES v0.14.0. However, most KES deployments
still use Hashicorp Vault as KMS backend and version before
v0.17.0 contain a serious Vault SDK consistency bug.

Signed-off-by: Andreas Auernhammer <hi@aead.dev>

internal/yml/config.go

@@ -153,20 +153,6 @@ func unmarshalServerConfig(b []byte) (*ServerConfig, error) {
 			if _, ok := errV0170.(*yaml.TypeError); !ok {
 				return nil, err
 			}
-
-			var configV0140 serverConfigV0140
-			if errV0140 := yaml.Unmarshal(b, &configV0140); errV0140 != nil {
-				if _, ok := errV0140.(*yaml.TypeError); !ok {
-					return nil, err
-				}
-
-				var configV0135 serverConfigV0135
-				if errV0135 := yaml.Unmarshal(b, &configV0135); errV0135 != nil {
-					return nil, err
-				}
-				return configV0135.migrate(), nil
-			}
-			return configV0140.migrate(), nil
 		}
 		return configV0170.migrate(), nil
 	}

internal/yml/server-config_test.go

@@ -9,9 +9,7 @@ import "testing"
 var readServerConfigTests = []struct {
 	File string
 }{
-	{File: "testdata/config_v0.13.0.yml"}, // 0
-	{File: "testdata/config_v0.14.0.yml"}, // 1
-	{File: "testdata/config_v0.17.0.yml"}, // 2
+	{File: "testdata/config_v0.17.0.yml"}, // 0
 }
 
 func TestReadServerConfig(t *testing.T) {