update copyright year

Author: chewiebug

src/main/java/com/tagtraum/perf/gcviewer/view/AboutDialog.java

@@ -89,7 +89,7 @@ public AboutDialog(Frame f) {
         versionPanel.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
         versionPanel.setLayout(new GridBagLayout());
 
-        JLabel copyright = new JLabel("\u00A9" + " 2011-2018: Joerg Wuethrich and contributors", JLabel.CENTER);
+        JLabel copyright = new JLabel("\u00A9" + " 2011-2019: Joerg Wuethrich and contributors", JLabel.CENTER);
 
         JLabel contributorsLabel = new JLabel("contributors (alphabetically ordered):", JLabel.CENTER);
         contributorsLabel.setForeground(Color.GRAY);