Add option to fetch tags even if fetch-depth > 0 (#579)

* Add option to fetch tags even if fetch-depth > 0

* Add jest tests for fetchDepth and fetchTags options

src/git-source-settings.ts

@@ -44,6 +44,11 @@ export interface IGitSourceSettings {
    */
   fetchDepth: number
 
+  /**
+   * Fetch tags, even if fetchDepth > 0 (default: false)
+   */
+  fetchTags: boolean
+
   /**
    * Indicates whether to fetch LFS objects
    */