Document workflow fails when `RoxygenNote:` is out of date in the `DESCRIPTION`

[Moohan]

Describe the bug Document workflow can modify the DESCRIPTION file (by updating the Roxygen version note) but it won't commit the change. This leads to a build error when there is nothing else to commit.

To Reproduce failed build

Run the action on a package which is 'properly' documented but has an older roxygen version in the DESCRIPTION

Expected behaviour Commit the change to the DESCRIPTION. Or do nothing but don't fail if only the DESCRIPTION is to be changed.