Add RFM69_LowPowerLab to the Library Manager index

[LowPowerLab]

Please update the library manager/index or add it if not already there.

https://github.com/LowPowerLab/RFM69

Thank you!

[cmaglie]

I've added the library but there is a problem:

JOB 1548 - 2018/05/10 19:34:29 Scraping https://github.com/LowPowerLab/RFM69.git
JOB 1548 - 2018/05/10 19:34:33 Checking out tag: 1.0
JOB 1548 - 2018/05/10 19:34:33 Error syncing library: *.exe files found, skipping
JOB 1548 - 2018/05/10 19:34:33 Checking out tag: 1.0.0
JOB 1548 - 2018/05/10 19:34:33 Error syncing library: *.exe files found, skipping

we do not allow to bundle executables in the library. To fix this:

1. remove all the executables from the library
2. commit & push
3. redo the release tag

Once done the library will be picked up automatically by our indexer within an hour, no need to comment further here.