Update 'parser' struct annotation in config.go

The 'parser' struct in config.go has been updated with Fig configuration annotation. This allows ease of configuration as it sources the configuration options from the environment, making the code cleaner and more flexible.

config.go

@@ -45,7 +45,7 @@ type Config struct {
 	Parser struct {
 		Type    string        `fig:"type" validate:"required"`
 		Timeout time.Duration `fig:"timeout" default:"500ms"`
-	}
+	} `fig:"parser"`
 	internal struct {
 		ParserType parsesyslog.ParserType
 	}