Support go 1.13

go.mod

@@ -1,3 +1,3 @@
 module ridi
 
-go 1.17
+go 1.13

main.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"html"
 	"io"
+	"io/ioutil"
 	"mime/multipart"
 	"net/http"
 	"net/url"
@@ -29,7 +30,7 @@ func handleMessage(client *http.Client, botToken string, message *Message) error
 	if len(split) == 2 {
 		command.Stdin = strings.NewReader(split[1])
 	}
-	stdout, err := os.CreateTemp("", "ridi*")
+	stdout, err := ioutil.TempFile("", "ridi*")
 	if err != nil {
 		return fmt.Errorf("failed to create temporary file: %s", err)
 	}

utils.go

@@ -3,13 +3,13 @@ package main
 import (
 	"encoding/json"
 	"fmt"
-	"io"
+	"io/ioutil"
 	"net/http"
 )
 
 func parseBody(resp *http.Response) (json.RawMessage, error) {
 	defer resp.Body.Close()
-	bytes, err := io.ReadAll(resp.Body)
+	bytes, err := ioutil.ReadAll(resp.Body)
 	if err != nil {
 		return nil, fmt.Errorf("failed to read response body: %s", err)
 	}