feat: use go:embed to embed templates (#1756)

tools/goctl/rpc/generator/call.tpl

@@ -0,0 +1,33 @@
+{{.head}}
+
+package {{.filePackage}}
+
+import (
+	"context"
+
+	{{.pbPackage}}
+	{{if ne .pbPackage .protoGoPackage}}{{.protoGoPackage}}{{end}}
+
+	"github.com/zeromicro/go-zero/zrpc"
+	"google.golang.org/grpc"
+)
+
+type (
+	{{.alias}}
+
+	{{.serviceName}} interface {
+		{{.interface}}
+	}
+
+	default{{.serviceName}} struct {
+		cli zrpc.Client
+	}
+)
+
+func New{{.serviceName}}(cli zrpc.Client) {{.serviceName}} {
+	return &default{{.serviceName}}{
+		cli: cli,
+	}
+}
+
+{{.functions}}