Fix pagination for mstdn command

cmd/mstdn/cmd_followers.go

@@ -3,6 +3,7 @@ package main
 import (
 	"context"
 	"fmt"
+	"time"
 
 	"github.com/mattn/go-mastodon"
 	"github.com/urfave/cli"
@@ -16,9 +17,20 @@ func cmdFollowers(c *cli.Context) error {
 	if err != nil {
 		return err
 	}
-	followers, err := client.GetAccountFollowers(context.Background(), account.ID)
-	if err != nil {
-		return err
+	var maxID *int64
+	var followers []*mastodon.Account
+	for {
+		fs, pg, err := client.GetAccountFollowers(
+			context.Background(), account.ID, &mastodon.Pagination{MaxID: maxID})
+		if err != nil {
+			return err
+		}
+		followers = append(followers, fs...)
+		if pg.MaxID == nil {
+			break
+		}
+		maxID = pg.MaxID
+		time.Sleep(10 * time.Second)
 	}
 	s := newScreen(config)
 	for _, follower := range followers {