print version on --version switch

src/common/Args.hpp

@@ -1,5 +1,7 @@
 #pragma once
 
+#include <QStringList>
+
 namespace chatterino {
 
 /// Command line arguments passed to Chatterino.
@@ -8,6 +10,7 @@ class Args
 public:
     Args(const QStringList &args);
 
+    bool printVersion{};
     bool crashRecovery{};
 };