add copy button

src/app/qgsabout.cpp

@@ -20,6 +20,7 @@
 #include "qgsauthmethodregistry.h"
 #include "qgsproviderregistry.h"
 #include "qgslogger.h"
+#include <QClipboard>
 #include <QDesktopServices>
 #include <QFile>
 #include <QTextStream>
@@ -43,6 +44,7 @@ QgsAbout::QgsAbout( QWidget *parent )
   setupUi( this );
   connect( btnQgisUser, &QPushButton::clicked, this, &QgsAbout::btnQgisUser_clicked );
   connect( btnQgisHome, &QPushButton::clicked, this, &QgsAbout::btnQgisHome_clicked );
+  connect( btnCopyToClipboard, &QPushButton::clicked, this, &QgsAbout::btnCopyToClipboard_clicked );
   if constexpr( QSysInfo::WordSize != 64 )
   {
     // 64 bit is the current standard. Only specify word size if it is not 64.
@@ -271,6 +273,12 @@ void QgsAbout::setPluginInfo()
   txtProviders->setText( myString );
 }
 
+void QgsAbout::btnCopyToClipboard_clicked()
+{
+  QString markdown = txtVersion->toHtml();
+  QGuiApplication::clipboard()->setText( markdown );
+}
+
 void QgsAbout::btnQgisUser_clicked()
 {
   openUrl( QStringLiteral( "https://lists.osgeo.org/mailman/listinfo/qgis-user" ) );

src/app/qgsabout.h

@@ -38,6 +38,7 @@ class APP_EXPORT QgsAbout : public QgsOptionsDialogBase, private Ui::QgsAbout
     void init();
 
   private slots:
+    void btnCopyToClipboard_clicked();
     void btnQgisUser_clicked();
     void btnQgisHome_clicked();
     void openUrl( const QUrl &url );

src/ui/qgsabout.ui

@@ -222,6 +222,13 @@
              </property>
             </widget>
            </item>
+           <item>
+            <widget class="QPushButton" name="btnCopyToClipboard">
+             <property name="text">
+              <string>Copy to Clipboard</string>
+             </property>
+            </widget>
+           </item>
            <item>
             <widget class="QLabel" name="label_3">
              <property name="text">