buf: modify buf.yml, add buf generate (#5653)

scripts/protocgen.sh

@@ -2,20 +2,7 @@
 
 set -eo pipefail
 
-proto_dirs=$(find ./proto -path -prune -o -name '*.proto' -print0 | xargs -0 -n1 dirname | sort | uniq)
-for dir in $proto_dirs; do
-  buf protoc \
-  -I "proto" \
-  -I "third_party/proto" \
-  --gogofaster_out=\
-Mgoogle/protobuf/timestamp.proto=github.com/gogo/protobuf/types,\
-Mgoogle/protobuf/duration.proto=github.com/golang/protobuf/ptypes/duration,\
-plugins=grpc,paths=source_relative:. \
-  $(find "${dir}" -maxdepth 1 -name '*.proto')
-done
-
-cp -r ./tendermint/* ./proto/*
-rm -rf tendermint
+buf generate --path proto/tendermint
 
 mv ./proto/tendermint/abci/types.pb.go ./abci/types