Update logger to allow a more generic level. (#14040)

logger/config.go

@@ -5,14 +5,15 @@ import (
 )
 
 type Config struct {
-	Format       string        `toml:"format"`
-	Level        zapcore.Level `toml:"level"`
-	SuppressLogo bool          `toml:"suppress-logo"`
+	Format       string               `toml:"format"`
+	Level        zapcore.LevelEnabler `toml:"level"`
+	SuppressLogo bool                 `toml:"suppress-logo"`
 }
 
 // NewConfig returns a new instance of Config with defaults.
 func NewConfig() Config {
 	return Config{
 		Format: "auto",
+		Level:  zapcore.Level(0),
 	}
 }