You might want to use the maintained 3.8 branch ( https://github.com/gnuradio/gnuradio/tree/maint-3.8 ) which was officially released 2019-08-09 instead of trying to use what is actively being coded right now.
If you look at the official pybombs recipe for gnuradio it currently points at the maint-3.8 branch and that would be what everyone else would be using.
This is how I would “pybombs install gr-limesdr” and/or “pybombs install gnuradio” from source code.