go.mod+lnrpc+github: point to latest kvdb changes

Use kvdb package v1.4.1. This update also forced the protobuf version to
be bumped which required `make rpc` to be run to update the generated
files. This also required a bump in the github pinned dependencies
config for the grpc and protobuf libs.

.github/workflows/main.yml

@@ -360,7 +360,7 @@ jobs:
       fail-fast: false
       matrix:
         pinned_dep:
-          - google.golang.org/grpc v1.38.0
+          - google.golang.org/grpc v1.41.0
           - github.com/golang/protobuf v1.5.2
 
     steps: