Change to https for tigervnc URL

Our main web site now supports https, so update all references.
diff --git a/release/tigervnc.iss.in b/release/tigervnc.iss.in
index 092345a..5850148 100644
--- a/release/tigervnc.iss.in
+++ b/release/tigervnc.iss.in
@@ -9,7 +9,7 @@
 #endif
 AppVersion=@VERSION@
 AppPublisher=TigerVNC project
-AppPublisherURL=http://tigervnc.org
+AppPublisherURL=https://tigervnc.org
 DefaultDirName={pf}\TigerVNC
 #ifdef WIN64
 DefaultGroupName=TigerVNC 64-bit