Fix linter

server/server_test.go

@@ -3,13 +3,13 @@ package server
 import (
 	"bufio"
 	"context"
+	"crypto/rand"
 	"encoding/base64"
 	"encoding/json"
 	"fmt"
 	"golang.org/x/crypto/bcrypt"
 	"heckel.io/ntfy/v2/user"
 	"io"
-	"math/rand"
 	"net/http"
 	"net/http/httptest"
 	"net/netip"