Bazel -> 4.1.0 (Reducing memory-related crash on Mac)

Similar Bazel crashes to what's reported here (github) or here (stackoverflow) was seen while building the prereqs image on macOS/Docker (16-inch intel mbp):

$ docker-compose build --no-cache common prereqs

...

Server terminated abruptly (error code: 14, error message: 'Socket closed', log file: '/root/.cache/bazel/_bazel_root/.../server/jvm.out')

------

failed to solve: rpc error: code = Unknown desc = executor failed running [/bin/sh -c bazel build javascript/net/grpc/web/... &&   cp $(bazel info bazel-genfiles)/javascript/net/grpc/web/protoc-gen-grpc-web   /usr/local/bin/protoc-gen-grpc-web]: exit code: 37

The reason is that Bazel will crash under memory pressure. And bumping Bazel version to 4.1.0 fixes it on my Macbook (2019 16-inch mbp) for default Docker on Macsetup (uses 2GB memory).

Although, ./scripts/run_basic_tests.sh would still crash with the same error, which is only fixable after bumping the runtime memory option (e.g. to 4GB) in Docker for Mac settings .

(Also big thanks @stanley-cheung for helping with the debugging :))

Protobuf

Updating Protobuf too because Bazel 4.0+ demands Protobuf 3.13+ (see bazelbuild/bazel#12887 (comment)).