Reference support

* Add support for reference repository parameter

---------

Co-authored-by: Diego Dompe <ddompe@gmail.com>

__test__/git-auth-helper.test.ts

@@ -762,6 +762,7 @@ async function setup(testName: string): Promise<void> {
     lfsInstall: jest.fn(),
     log1: jest.fn(),
     remoteAdd: jest.fn(),
+    referenceAdd: jest.fn(),
     removeEnvironmentVariable: jest.fn((name: string) => delete git.env[name]),
     revParse: jest.fn(),
     setEnvironmentVariable: jest.fn((name: string, value: string) => {
@@ -821,7 +822,8 @@ async function setup(testName: string): Promise<void> {
     sshStrict: true,
     workflowOrganizationId: 123456,
     setSafeDirectory: true,
-    githubServerUrl: githubServerUrl
+    githubServerUrl: githubServerUrl,
+    reference: '/some/path'
   }
 }