Good practice != Something that ensures security. As I said, it's an even better practice to just host your own fork if what you want is security. The reason to use git hashes is mostly so you don't have to trust the author following semver in there version number. It's a matter of ensuring that your code will always compile, not a security feature.

Have you read the article? Your arguments derive from an assumption of "sha1 is mutable, sha256 is immutable". First of all, every hashing algorithm is going to have collisions, that's an unavoidable "feature" of hashes. And sha1 is in no way "mutable", it takes a great amount of effort (and money) to generate a collision. Furthermore, those collisions are not arbitrary. You have to calculate them beforehand. As the article says: what is more likely? Paying 40k€ in compute time to generate a single collision? Or just paying an open source maintainer 40k€ to let you do 1 new commit that most people are going to download anyway?