Doc: Fix date format

918145dc · Antoni Bella Pérez · 74bff080 · 918145dc
Commit 918145dc authored Jun 05, 2021 by Antoni Bella Pérez 🚵🏻
--- a/doc/index.docbook
+++ b/doc/index.docbook
@@ -25,7 +25,7 @@
 </copyright>
 <legalnotice>&FDLNotice;</legalnotice>

-<date>2021-04-06</date>
+<date>2021-06-04</date>
 <releaseinfo>KDE Gear 21.04</releaseinfo>

 <abstract>