package/expect: update Kconfig package URL

The old expect homepage URL [1] is now redirecting to [2]. This commit
updates the URL to the new one.

[1] http://expect.sourceforge.net/
[2] https://core.tcl.tk/expect/

Signed-off-by: Julien Olivain <ju.o@free.fr>
Signed-off-by: Arnout Vandecappelle <arnout@mind.be>

package/expect/Config.in

@@ -4,4 +4,4 @@ config BR2_PACKAGE_EXPECT
 	  Expect is a tool for automating interactive applications
 	  such as telnet, ftp, passwd, fsck, rlogin, ssh, tip, etc.
 
-	  http://expect.sourceforge.net/
+	  https://core.tcl.tk/expect/