docs(git): add gitignore template repo (#7104)

src/data/roadmaps/git-github/content/gitignore@oz2oRAhaEQb0Fm3aRJQG8.md

@@ -7,3 +7,4 @@ Visit the following resources to learn more:
 - [@official@gitignore Documentation](https://git-scm.com/docs/gitignore/en)
 - [@article@.gitignore file - ignoring files in Git | Atlassian Git Tutorial](https://www.atlassian.com/git/tutorials/saving-changes/gitignore)
 - [@article@Ignoring files - GitHub Docs](https://docs.github.com/en/get-started/getting-started-with-git/ignoring-files)
+- [@opensource@gitignore - A collection of useful .gitignore templates](https://github.com/github/gitignore)