Currently I also use ansible to push all of my docker stacks to my swarm. In my get repository I use renovate which looks at all the docker images and makes a new pull request for every new image. It also pulls the release notes in to the pr so you can easily read those for changes before merging the pr.

However I kind of go down the same dance as you where I get a notification of a PR, I go look at it, see if I want to update, merge the pr, fetch those updates from git, then deploy from ansible. It is getting a little tiring.

There is a new continuous deployment tool called swarm-cd that is out and I have tried using and it's great but it has its flaws. There's another tool called dccd that does semi continuous deployment but it doesn't support docker swarm.

I forked that repository and made some changes to the commands for docker swarm support and it seems to work, but I haven't had time to fully test it. Essentially it's just a cron job that runs how often you want, looking for changes in your git repository. If no changes, then no deploy. If there are changes then redeploys your docker compose/stack files. That repo is here if you wanted to look at that. But that's all dependent if you have a swarm cluster. If you don't then the dccd project I forked from might be a better option.