code: Small cleanups and fixes to lambda captures (#6191)

Co-authored-by: v1993 <v19930312@gmail.com>
Co-authored-by: Morph <39850852+Morph1984@users.noreply.github.com>

src/citra_qt/updater/updater.cpp

@@ -156,7 +156,7 @@ void UpdaterPrivate::StopUpdateCheck(int delay, bool async) {
             QTimer* timer = new QTimer(this);
             timer->setSingleShot(true);
 
-            connect(timer, &QTimer::timeout, [=]() {
+            connect(timer, &QTimer::timeout, [this, timer]() {
                 StopUpdateCheck(0, false);
                 timer->deleteLater();
             });