I2C address instructions for tipping bucket

[fisherba]

I suggest that the readme file for the tipping bucket I2C address instructions be changed. We now use the same hardware for wind and rain, so it's common to have both on the same station. The software I2C has been problematic, so we use the Salve_TippingBucket_Test.ino to assign the I2C address to each Pro Trinket as they are programmed. If the instructions could reflect that, it would be most helpful.

[SRGDamia1]

Can you submit a pull request or post new text for me to add?