feat(techdocs-common): update tests Azure Blob Storage

packages/techdocs-common/__mocks__/@azure/identity.ts

@@ -1 +1,20 @@
-export class DefaultAzureCredential {}
+/*
+ * Copyright 2020 Spotify AB
+ *
+ * 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.
+ */
+export class DefaultAzureCredential {
+  /**
+   * Creates an instance of the DefaultAzureCredential class.
+   */
+}