So you want to upgrade a library but don’t know what’s changed? Easy enough to do in git. Most projects tag their releases with something like v1.2.3. If you want to see all the commits between two of these releases simply do:
git log --no-merges v1.2.3 --not v1.2.2
This shows all commits from v1.2.3 that aren’t in v1.2.2.
Or if you want a short summary grouped by author you can do:
git shortlog --no-merges v1.2.3 --not v1.2.2