Write a script to update practracker on multiple branches

When we have 0.4.1 and 0.4.2 with practracker, and a backport branch makes a practice worse, we will need to update the practracker exceptions in multiple branches:

1. Update the exceptions in 0.4.1
2. Ours merge to 0.4.2
3. Update the exceptions in 0.4.2

If we automate this process, we can make it faster and more reliable.