How to change a release on Github point to the latest commit?

You would need to update/move the tag locally first, and force push it (as in here):

# assuming you are in the branch referencing currently the right new commit:
git tag -f <tagname>

# push your new commit:
git push 

# force push your moved tag:
git push origin -f <tagname>

Then you can go on GitHub and associate new binaries with the release for that tag (which should point to the right commit).