Updated dependencies

Fixes

Update dependency bazel_gazelle to v0.19.1 (#508)
update rules_docker & other deps (#510)
Update dependency build_bazel_rules_nodejs to v1 (#503)
Update dependency io_bazel_rules_go to v0.21.0 (#501)
Update rules_docker pin (#496)
Propagate docker publish error message (#500)
Update dependency com_github_grpc_grpc to v1.26.0 (#494)
Update build_stack_rules_proto commit hash to 0a888db (#493)
Update dependency com_google_protobuf to v3.11.2 (#483)
Update dependency io_bazel_rules_go to v0.20.3 (#482)
Update rules_python commit hash to 38f86fb (#480)
Update dependency com_google_protobuf to v3.11.0 (#478)
Update io_bazel_rules_jsonnet commit hash to 1297986 (#476)
Update rules_python commit hash to 9467740 (#474)
Update rules_python commit hash to 7b222cf (#473)
Update rules_python commit hash to 13bf8b7 (#472)
Update dependency com_github_grpc_grpc to v1.25.0 (#471)
Remove PY2 notice from the README (#462)
Update README for v0.3.1 (#470)