Update Kanboard version to 1.2.11

Install/kanboard-install

@@ -5,7 +5,7 @@
 # Install Kanboard
 
 ## Find the latest release on https://github.com/kanboard/kanboard/releases
-set version '1.2.10'
+set version '1.2.11'
 
 ## PostgreSQL setup
 sudo -u postgres psql -f Templates/postgres_kanboard.sql