Port away from deprecated QTimeLine::setCurveShape()

lib/thumbnailview/thumbnailview.cpp

@@ -199,7 +199,7 @@ struct ThumbnailViewPrivate
     {
         mBusySequence = KIconLoader::global()->loadPixmapSequence(QStringLiteral("process-working"), 22);
         mBusyAnimationTimeLine = new QTimeLine(100 * mBusySequence.frameCount(), q);
-        mBusyAnimationTimeLine->setCurveShape(QTimeLine::LinearCurve);
+        mBusyAnimationTimeLine->setEasingCurve(QEasingCurve::Linear);
         mBusyAnimationTimeLine->setEndFrame(mBusySequence.frameCount() - 1);
         mBusyAnimationTimeLine->setLoopCount(0);
         QObject::connect(mBusyAnimationTimeLine, &QTimeLine::frameChanged, q, &ThumbnailView::updateBusyIndexes);