Replace boost::optional with std::optional (#4877)

src/widgets/helper/Button.hpp

@@ -2,7 +2,6 @@
 
 #include "widgets/BaseWidget.hpp"
 
-#include <boost/optional.hpp>
 #include <QMenu>
 #include <QMouseEvent>
 #include <QPainter>
@@ -10,6 +9,8 @@
 #include <QTimer>
 #include <QWidget>
 
+#include <optional>
+
 namespace chatterino {
 
 class Button : public BaseWidget
@@ -31,7 +32,7 @@ public:
 
     Button(BaseWidget *parent = nullptr);
 
-    void setMouseEffectColor(boost::optional<QColor> color);
+    void setMouseEffectColor(std::optional<QColor> color);
     void setPixmap(const QPixmap &pixmap_);
     const QPixmap &getPixmap() const;
 
@@ -94,7 +95,7 @@ private:
     double hoverMultiplier_{0.0};
     QTimer effectTimer_{};
     std::vector<ClickEffect> clickEffects_{};
-    boost::optional<QColor> mouseEffectColor_{};
+    std::optional<QColor> mouseEffectColor_{};
     std::unique_ptr<QMenu> menu_{};
 };