main: ioutil.ReadFile is deprecated

Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>

main.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
 	"os"
 
 	"github.com/mattn/go-mastodon"
@@ -44,7 +43,7 @@ func main() {
 				ClientSecret: "asfdasdfasfd",
 				AccessToken:  "asdfasdfadfasfd",
 			}
-			buf, err := ioutil.ReadFile(ctx.String("config"))
+			buf, err := os.ReadFile(ctx.String("config"))
 			if err == nil {
 				tmpconfig := mastodon.Config{}
 				err := json.Unmarshal(buf, &tmpconfig)