/etc/sudoers.d regex is incomplete

There are rules (e.g. `sudo_require_reauthentication`, but probably others) that check `sudo`'s configuration by scanning `/etc/sudoers` and all files in `/etc/sudoers.d`. For example, `sudo_require_reauthentication` uses the regex `^\/etc\/(sudoers|sudoers\.d\/.*)$`.

This is mostly correct, assuming `/etc/sudoers` actually has an includedir for that directory, but `sudo` ignores certain filename patterns. From the `sudoers` man page:

> For example, given:
>
> @includedir /etc/sudoers.d
>
> sudo will suspend processing of the current file and read each file in /etc/sudoers.d, skipping file names that end in ‘~’ or contain a ‘.’ character to avoid causing problems with package manager or editor temporary/backup files.

So if `/etc/sudoers.d/example.conf` contains `Defaults timestamp_timeout=1`, `sudo` will ignore it but an oscap run will mark it as passing.