Git min requirements (#8177)

* Add minimum git requirements.

* Added comments about git lfs and commit-graph

* Fix capitalization

Author: guillep2k

docs/content/page/index.en-us.md

@@ -255,6 +255,9 @@ Windows, on architectures like amd64, i386, ARM, PowerPC, and others.
 - 2 CPU cores and 1GB RAM is typically sufficient for small teams/projects.
 - Gitea should be run with a dedicated non-root system account on UNIX-type systems.
    - Note: Gitea manages the `~/.ssh/authorized_keys` file. Running Gitea as a regular user could break that user's ability to log in.
+- [Git](https://git-scm.com/) version 1.7.2 or later is required. Version 1.9.0 or later is recommended. Also please note:
+   - Git [large file storage](https://git-lfs.github.com/) will be available if enabled when git >= 2.1.2.
+   - Git commit-graph rendering will be enabled automatically when git >= 2.18.
 
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