package/libconfig: bump to version 1.8.1

For change log, see:

https://github.com/hyperrealm/libconfig/releases/tag/v1.8.1

The download URL now points to
https://hyperrealm.github.io/libconfig/dist.

The COPYING.LIB file has been changed. See the following commit for
details:

https://github.com/hyperrealm/libconfig/commit/be4da0c2fd5d08cefb628af67b68d32907fc972a

Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
Signed-off-by: Julien Olivain <ju.o@free.fr>

package/libconfig/libconfig.hash

@@ -1,3 +1,3 @@
 # Locally computed:
-sha256  545166d6cac037744381d1e9cc5a5405094e7bfad16a411699bcff40bbb31ee7  libconfig-1.7.3.tar.gz
-sha256  d80c9d084ebfb50ea1ed91bfbc2410d6ce542097a32c43b00781b83adcb8c77f  COPYING.LIB
+sha256  87c6f382994b245f9213be34a2bf19c8ee7d033d7abaa51e88fbb7bad79e2dc6  libconfig-1.8.1.tar.gz
+sha256  cbbad55f94feadb16061c4f782910bac254460a44f1c8abd2b91452eff085f55  COPYING.LIB

package/libconfig/libconfig.mk

@@ -4,8 +4,8 @@
 #
 ################################################################################
 
-LIBCONFIG_VERSION = 1.7.3
-LIBCONFIG_SITE = https://github.com/hyperrealm/libconfig/releases/download/v$(LIBCONFIG_VERSION)
+LIBCONFIG_VERSION = 1.8.1
+LIBCONFIG_SITE = https://hyperrealm.github.io/libconfig/dist
 LIBCONFIG_LICENSE = LGPL-2.1+
 LIBCONFIG_LICENSE_FILES = COPYING.LIB
 LIBCONFIG_INSTALL_STAGING = YES