Updated Sept. 2022

By default, OP25 now builds for Python3 and GNU Radio3.8.
Accordingly, it is no longer necessary to apply the op25 patch 
for gr3.8.

It should be possible to use the gr3.8.patch in reverse to downgrade
the source tree to build for Python 2 and GNU Radio 3.7.  See the 
file README in this directory for details.