feat: yaml output formatter

core/output/formatter.go

@@ -6,7 +6,7 @@ import (
 
 var Formatters = map[string]interfaces.Formatter{
 	"json":  &JsonFormatter{},
-	"yaml":  nil,
+	"yaml":  &YamlFormatter{},
 	"go":    &GoFormatter{},
 	"table": nil,
 }

core/output/yaml.go

@@ -0,0 +1,19 @@
+package output
+
+import (
+	"bytes"
+	"io"
+
+	"github.com/goccy/go-yaml"
+)
+
+type YamlFormatter struct{}
+
+func (f *YamlFormatter) Format(object any) (io.Reader, error) {
+	buffer, err := yaml.Marshal(object)
+	if err != nil {
+		return nil, err
+	}
+
+	return bytes.NewBuffer(buffer), nil
+}