sort of an automation, but I install all my favorite apps with brew and then use brew again (brew upgrade && brew upgrade --cask -g) to update everything
Bonus: I went the extra mile and wrote a script that bootstraps my entire setup: https://github.com/fastily/autobots/blob/master/macOS/setup/...
Brew supports dumping installed things into a brewfile: https://github.com/Homebrew/homebrew-bundle
I was using text files before as well to manage it.