pass in the specified git branch ref when cloning a single branch

plugins/scaffolder-backend/src/scaffolder/stages/prepare/github.test.ts

@@ -89,6 +89,7 @@ describe('GitHubPreparer', () => {
     expect(mockGitClient.clone).toHaveBeenCalledWith({
       url: 'https://github.com/benjdlambert/backstage-graphql-template',
       dir: expect.any(String),
+      ref: expect.any(String),
     });
   });
 
@@ -100,6 +101,7 @@ describe('GitHubPreparer', () => {
     expect(mockGitClient.clone).toHaveBeenCalledWith({
       url: 'https://github.com/benjdlambert/backstage-graphql-template',
       dir: expect.any(String),
+      ref: expect.any(String),
     });
   });
 

plugins/scaffolder-backend/src/scaffolder/stages/prepare/github.ts

@@ -42,6 +42,7 @@ export class GithubPreparer implements PreparerBase {
 
     const parsedGitLocation = parseGitUrl(location);
     const repositoryCheckoutUrl = parsedGitLocation.toString('https');
+    const ref = parsedGitLocation.ref;
     const tempDir = await fs.promises.mkdtemp(
       path.join(workingDirectory, templateId),
     );
@@ -63,6 +64,7 @@ export class GithubPreparer implements PreparerBase {
 
     await git.clone({
       url: repositoryCheckoutUrl,
+      ref: ref,
       dir: tempDir,
     });