Fix issue due to PlasmaCalendar returning wrong year

PlasmaCalendar year property is returning 0, what breaks the logic of
getting which was the day of the week of Jan 1st, current year.
This commit relies on JS Date object functions to get the current year.
Also, it fixes a old and dumb issue in this plasmoid due to the fact
January in JavaScript is 0, not 1.

contents/ui/CompactRepresentation.qml

@@ -15,7 +15,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-import QtQuick 2.0
+import QtQuick 2.12
 import QtQuick.Layouts 1.1
 import org.kde.plasma.components 2.0 as PlasmaComponents
 import org.kde.plasma.calendar 2.0 as PlasmaCalendar
@@ -38,10 +38,11 @@ PlasmaComponents.Label {
 
     if (plasmoid.configuration.firstWeekOfYearIndex == 1) {
       // Check if January 1st is after Wednesday.
-      var date = new Date(calendarBackend.year, 1, 1);
-      var firstJanDayofWeek = date.getDay();
+      var date = new Date();
+      var janFirst = new Date(date.getFullYear(), 0, 1); // January is 0 in JS
+      var janFirstDayOfWeek = janFirst.getDay();
       // Wednesday == 3, week starting on Sunday
-      if (firstJanDayofWeek > 3)
+      if (janFirstDayOfWeek > 3)
         week = week + 1;
     }
     return week < 10 ? "0" + week : week