chore: add note to the FAQ for git version support (#569)

* chore: add note to the FAQ for git version support in the use of `git log --pretty`

Co-authored-by: fisher <[email protected]>

readme.md

@@ -641,7 +641,17 @@ There are a few potential reasons:
   to output its logs add `@kwsites/file-exists` to your `DEBUG` environment variable. eg:
 
   `DEBUG=@kwsites/file-exists,simple-git node ./your-app.js`
-
+
+### Log format fails
+
+The properties of `git log` are fetched using the `--pretty=format` argument which supports different tokens depending
+on the version of `git` - for example the `%D` token used to show the refs was added in git `2.2.3`, for any version
+before that please ensure you are supplying your own format object with properties supported by the version of git you
+are using.
+
+For more details of the supported tokens, please see the
+[official `git log` documentation](https://git-scm.com/docs/git-log#_pretty_formats) 
+
 ### Log response properties are out of order
 
 The properties of `git.log` are fetched using the character sequence ` ò ` as a delimiter. If your commit messages