fix: installation of plugins for Go v1.18 and above (#2174)

* Run go install after go get to install plugins

This fixes #1163, but is not ideal... tooling binaries should be installed by running `go install [path]@[version]`, but protoc-gen-gocosmos uses a replace directive in the `go.mod` which is [incompatible with this method](golang/go#44840 (comment)). This fixes the problem for now, but adds plugin specific items to the go.mod of the scaffolded project, which shouldn't be there.

* Update starport/pkg/cosmosgen/install.go

Co-authored-by: İlker G. Öztürk <ilkergoktugozturk@gmail.com>

starport/pkg/cosmosgen/install.go

@@ -11,29 +11,28 @@ import (
 
 // InstallDependencies installs protoc dependencies needed by Cosmos ecosystem.
 func InstallDependencies(ctx context.Context, appPath string) error {
+	plugins := []string{
+		// installs the gocosmos plugin.
+		"github.com/regen-network/cosmos-proto/protoc-gen-gocosmos",
+
+		// install Go code generation plugin.
+		"github.com/golang/protobuf/protoc-gen-go",
+
+		// install grpc-gateway plugins.
+		"github.com/grpc-ecosystem/grpc-gateway/protoc-gen-grpc-gateway",
+		"github.com/grpc-ecosystem/grpc-gateway/protoc-gen-swagger",
+		"github.com/grpc-ecosystem/grpc-gateway/v2/protoc-gen-openapiv2",
+	}
+
 	errb := &bytes.Buffer{}
 	err := cmdrunner.
 		New(
 			cmdrunner.DefaultStderr(errb),
 			cmdrunner.DefaultWorkdir(appPath),
 		).
 		Run(ctx,
-			step.New(
-				step.Exec(
-					"go",
-					"get",
-					// installs the gocosmos plugin.
-					"github.com/regen-network/cosmos-proto/protoc-gen-gocosmos",
-
-					// install Go code generation plugin.
-					"github.com/golang/protobuf/protoc-gen-go",
-
-					// install grpc-gateway plugins.
-					"github.com/grpc-ecosystem/grpc-gateway/protoc-gen-grpc-gateway",
-					"github.com/grpc-ecosystem/grpc-gateway/protoc-gen-swagger",
-					"github.com/grpc-ecosystem/grpc-gateway/v2/protoc-gen-openapiv2",
-				),
-			),
+			step.New(step.Exec("go", append([]string{"get"}, plugins...)...)),
+			step.New(step.Exec("go", append([]string{"install"}, plugins...)...)),
 		)
 	return errors.Wrap(err, errb.String())
 }