A client wants to keep one of their permanent job listing posts (on a WordPress-based site) in good SEO standing and is afraid that a post date going back to 2015 will negatively impact the SEO of this job listing post. They're curious if they could have the post automatically update the publish date periodically. I haven't come across an easy way to have the site do that periodically, but I did find this post about updating a post's date to the current date/time.
My concern is that Google will flag the post as spam because the post date keeps changing (even if I found a way to automatically update periodically), or that it will otherwise negatively affect SEO. What would the potential impact be on SEO for this case?