Use indentation of 2 when rewriting auto-migrated config file

This seems to be what most people use when indenting yaml files, and it seems to
make more sense than the default of 4.

We also use it the example config in Config.md.

pkg/utils/yaml_utils/yaml_utils.go

@@ -1,6 +1,7 @@
 package yaml_utils
 
 import (
+	"bytes"
 	"errors"
 	"fmt"
 
@@ -34,7 +35,7 @@ func UpdateYamlValue(yamlBytes []byte, path []string, value string) ([]byte, err
 	}
 
 	// Convert the updated YAML node back to YAML bytes.
-	updatedYAMLBytes, err := yaml.Marshal(body)
+	updatedYAMLBytes, err := yamlMarshal(body)
 	if err != nil {
 		return nil, fmt.Errorf("failed to convert YAML node to bytes: %w", err)
 	}
@@ -126,7 +127,7 @@ func TransformNode(yamlBytes []byte, path []string, transform func(node *yaml.No
 	}
 
 	// Convert the updated YAML node back to YAML bytes.
-	updatedYAMLBytes, err := yaml.Marshal(body)
+	updatedYAMLBytes, err := yamlMarshal(body)
 	if err != nil {
 		return nil, fmt.Errorf("failed to convert YAML node to bytes: %w", err)
 	}
@@ -170,7 +171,7 @@ func RenameYamlKey(yamlBytes []byte, path []string, newKey string) ([]byte, erro
 	}
 
 	// Convert the updated YAML node back to YAML bytes.
-	updatedYAMLBytes, err := yaml.Marshal(body)
+	updatedYAMLBytes, err := yamlMarshal(body)
 	if err != nil {
 		return nil, fmt.Errorf("failed to convert YAML node to bytes: %w", err)
 	}
@@ -227,7 +228,7 @@ func Walk(yamlBytes []byte, callback func(node *yaml.Node, path string) bool) ([
 	}
 
 	// Convert the updated YAML node back to YAML bytes.
-	updatedYAMLBytes, err := yaml.Marshal(body)
+	updatedYAMLBytes, err := yamlMarshal(body)
 	if err != nil {
 		return nil, fmt.Errorf("failed to convert YAML node to bytes: %w", err)
 	}
@@ -273,3 +274,12 @@ func walk(node *yaml.Node, path string, callback func(*yaml.Node, string) bool)
 
 	return didChange, nil
 }
+
+func yamlMarshal(node *yaml.Node) ([]byte, error) {
+	var buffer bytes.Buffer
+	encoder := yaml.NewEncoder(&buffer)
+	encoder.SetIndent(2)
+
+	err := encoder.Encode(node)
+	return buffer.Bytes(), err
+}