Fix for Pi Temp in NavBar Temp Plugin

Just a note for those who use the NavBar Temp plugin on a Raspberry Pi 4 and have missed the reporting of the Pi CPU temperature ... I located the issue in the source and have fixed my own installation. It's fairly simple if you're familiar with editing files on the Pi.

The solution is in a thread regarding the issue on GitHub and can be found here.

I see there's already a pull request to make the fix ...

Yes this problem occurs on Octopi 18.1 beta but not on 17. Will try the fix.

I tried but the path doesn't exist. I suspect in my case I would need to change the path to Python 3.