Support 2.1.28

[SebastienGllmt]

This commit ankitects/anki@769bf04 removed the deckDueList function. Thanks to glutanimate/anki-addons-misc#152 for showing how to fix this issue

[felurx]

@SebastienGllmt It'd be awesome if you could merge this (and publish an update). Are there any issues with this / anything left to do before you can merge?
Your add-on is pretty useful and it'd be great to have it working again.

[SebastienGllmt]

This PR works as-is. I have just left it open to make it easier for other people to find. I haven't pushed the update to Anki simply due to laziness on my part (sorry!)

[felurx]

Ah, understandable 😅
I don't know if this is the correct way, but if someone wants to use this plugin with new versions, here's a workaround:

1. git clone https://github.com/SebastienGllmt/Anki-Addons/
2. cd Anki-Addons
3. git checkout 2.1.28-support
4. In Anki, go to Extras->Add-Ons, choose Throughput Monitor
5. Enable it
6. Click 'Show Files'
7. Copy all files from Anki-Addons/addons21/ThroughputMonitor into the 826650564 folder Anki opened, override all files
8. Restart Anki

This will probably cause problems in the future. Maybe Anki's updater will take care of it, but removing and reinstalling the add-on should do the trick :D