Marshaler incorrectly marshals date strings

[467892746]

The marshaler should quote strings that have YAML's date format. For example, the go string "2024-09-19T01:52:55.944" should be marshaled as '2024-09-19T01:52:55.944', with the quotes, but is currently marshaled without quotes.

SSCCE:

package main

import (
	"fmt"
	"gopkg.in/yaml.v3"
)

func main() {
	m := make(map[string]string)
	m["foo"] = "2024-09-19T01:52:55.944"
	out, _ := yaml.Marshal(m)
	fmt.Println(string(out))
}

Should output:

foo: '2024-09-19T01:52:55.944'

But instead outputs

foo: 2024-09-19T01:52:55.944