message: Update copyright year in about dialog
diff: </font>
  </property>
  <property name="text">
  - <string>Copyright &amp;copy; Baldur Karlsson 2020</string>
  + <string>Copyright &amp;copy; Baldur Karlsson 2021</string>
  </property>
  <property name="textFormat">
  <enum>Qt::RichText</enum>
  