Lnd-grpc

* Fixes from model on channel persistence: https://github.com/willcl-ark/lnd_grpc/pull/72

* Refactored some test code to remove RPC commands being removed in Bitcoin Core v0.19

* Incremental updates to dependencies

Bugfix: process defaultRPCPort as string during instantiation

Improve compatibility now with Python >=3.6

v 0.3.0 of lnd-grpc

* Loop support added b4605ee
* Hold invoices added c4cff1c
* Split into logical modular components d185c6a
* Static channel backups a674ee6
* Bump LND and Bitcoin Core versions f7c41bd
* Add configs c12eb2e
* Better package importing b3ee6a7 and 2d4b12c