fix(internal/postprocessor): add missing assignment (googleapis#8646)

Added a test so this is actually verified now too.

internal/postprocessor/config.go

@@ -98,6 +98,7 @@ func (p *postProcessor) loadConfig() error {
 			ServiceConfig: v.ServiceConfig,
 			ImportPath:    v.ImportPath,
 			RelPath:       v.RelPath,
+			ReleaseLevel:  v.ReleaseLevelOverride,
 		}
 	}
 	for _, v := range owlBotConfig.DeepCopyRegex {

internal/postprocessor/config_test.go

@@ -0,0 +1,41 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import "testing"
+
+func TestLoadConfig(t *testing.T) {
+	p := &postProcessor{
+		googleCloudDir: "../..",
+		googleapisDir:  googleapisDir,
+	}
+	if err := p.loadConfig(); err != nil {
+		t.Fatal(err)
+	}
+
+	li := p.config.GoogleapisToImportPath["google/cloud/alloydb/connectors/v1"]
+	if got, want := li.ImportPath, "cloud.google.com/go/alloydb/connectors/apiv1"; got != want {
+		t.Errorf("got %v, want %v", got, want)
+	}
+	if got, want := li.ServiceConfig, "connectors_v1.yaml"; got != want {
+		t.Errorf("got %v, want %v", got, want)
+	}
+	if got, want := li.RelPath, "/alloydb/connectors/apiv1"; got != want {
+		t.Errorf("got %v, want %v", got, want)
+	}
+	if got, want := li.ReleaseLevel, "preview"; got != want {
+		t.Errorf("got %v, want %v", got, want)
+	}
+}