chore: upgrade rules_go to 0.49.0

* upgrade bazel_gazelle to 0.38.0
* upgrade com_google_protobuf to 25.4
* add rules_proto 6.0.2
* remove -use_generic_streams_experimental
  * fix error: protoc-gen-go-grpc: no such flag -use_generic_streams_experimental

refs: googleapis#1554

WORKSPACE

@@ -19,15 +19,31 @@ bazel_skylib_workspace()
 
 http_archive(
     name = "com_google_protobuf",
-    sha256 = "d19643d265b978383352b3143f04c0641eea75a75235c111cc01a1350173180e",
-    strip_prefix = "protobuf-25.3",
-    urls = ["https://github.com/protocolbuffers/protobuf/archive/v25.3.tar.gz"],
+    sha256 = "af9236a5b5b0f641b20f5511c1e4527efa981ac91d7342c6b1033f4f03bc5d21",
+    strip_prefix = "protobuf-25.4",
+    urls = ["https://github.com/protocolbuffers/protobuf/archive/v25.4.tar.gz"],
 )
 
 load("@com_google_protobuf//:protobuf_deps.bzl", "protobuf_deps")
 
 protobuf_deps()
 
+http_archive(
+    name = "rules_proto",
+    sha256 = "6fb6767d1bef535310547e03247f7518b03487740c11b6c6adb7952033fe1295",
+    strip_prefix = "rules_proto-6.0.2",
+    url = "https://github.com/bazelbuild/rules_proto/releases/download/6.0.2/rules_proto-6.0.2.tar.gz",
+)
+
+load("@rules_proto//proto:repositories.bzl", "rules_proto_dependencies")
+rules_proto_dependencies()
+
+load("@rules_proto//proto:setup.bzl", "rules_proto_setup")
+rules_proto_setup()
+
+load("@rules_proto//proto:toolchains.bzl", "rules_proto_toolchains")
+rules_proto_toolchains()
+
 http_archive(
     name = "com_google_googleapis",
     # Use `master` because googleapis isn't semantically versioned and the protos
@@ -42,19 +58,19 @@ switched_rules_by_language(name = "com_google_googleapis_imports", go = True, gr
 
 http_archive(
     name = "io_bazel_rules_go",
-    sha256 = "f74c98d6df55217a36859c74b460e774abc0410a47cc100d822be34d5f990f16",
+sha256 = "d93ef02f1e72c82d8bb3d5169519b36167b33cf68c252525e3b9d3d5dd143de7",
     urls = [
-        "https://mirror.bazel.build/github.com/bazelbuild/rules_go/releases/download/v0.47.1/rules_go-v0.47.1.zip",
-        "https://github.com/bazelbuild/rules_go/releases/download/v0.47.1/rules_go-v0.47.1.zip",
+        "https://mirror.bazel.build/github.com/bazelbuild/rules_go/releases/download/v0.49.0/rules_go-v0.49.0.zip",
+        "https://github.com/bazelbuild/rules_go/releases/download/v0.49.0/rules_go-v0.49.0.zip",
     ],
 )
 
 http_archive(
     name = "bazel_gazelle",
-    sha256 = "75df288c4b31c81eb50f51e2e14f4763cb7548daae126817247064637fd9ea62",
+    sha256 = "8ad77552825b078a10ad960bec6ef77d2ff8ec70faef2fd038db713f410f5d87",
     urls = [
-        "https://storage.googleapis.com/bazel-mirror/github.com/bazelbuild/bazel-gazelle/releases/download/v0.36.0/bazel-gazelle-v0.36.0.tar.gz",
-        "https://github.com/bazelbuild/bazel-gazelle/releases/download/v0.36.0/bazel-gazelle-v0.36.0.tar.gz",
+        "https://storage.googleapis.com/bazel-mirror/github.com/bazelbuild/bazel-gazelle/releases/download/v0.38.0/bazel-gazelle-v0.38.0.tar.gz",
+        "https://github.com/bazelbuild/bazel-gazelle/releases/download/v0.38.0/bazel-gazelle-v0.38.0.tar.gz",
     ],
 )
 

showcase/showcase.bash

@@ -47,7 +47,6 @@ protoc \
 	--experimental_allow_proto3_optional \
 	--go_out ./gen \
 	--go-grpc_out ./gen \
-	--go-grpc_opt=use_generic_streams_experimental=false \
 	--go_gapic_out ./gen \
 	--go_gapic_opt 'transport=rest+grpc' \
 	--go_gapic_opt 'rest-numeric-enums' \