provide vendor dir for nix

vendor/github.com/spf13/viper/internal/encoding/json/codec.go

@@ -0,0 +1,17 @@
+package json
+
+import (
+	"encoding/json"
+)
+
+// Codec implements the encoding.Encoder and encoding.Decoder interfaces for JSON encoding.
+type Codec struct{}
+
+func (Codec) Encode(v map[string]any) ([]byte, error) {
+	// TODO: expose prefix and indent in the Codec as setting?
+	return json.MarshalIndent(v, "", "  ")
+}
+
+func (Codec) Decode(b []byte, v map[string]any) error {
+	return json.Unmarshal(b, &v)
+}