package/libpng: bump version to 1.6.43

Release notes:
https://sourceforge.net/p/png-mng/mailman/message/58741099/

Signed-off-by: Bernd Kuhls <bernd@kuhls.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit ce3ce432feda336e4476eb930353fed8e3318539)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libpng/libpng.hash

@@ -1,4 +1,4 @@
-# From https://sourceforge.net/p/png-mng/mailman/message/58731120/
-sha256  c919dbc11f4c03b05aba3f8884d8eb7adfe3572ad228af972bb60057bdb48450  libpng-1.6.42.tar.xz
+# From https://sourceforge.net/p/png-mng/mailman/message/58741099/
+sha256  6a5ca0652392a2d7c9db2ae5b40210843c0bbc081cbd410825ab00cc59f14a6c  libpng-1.6.43.tar.xz
 # Locally computed:
 sha256  7317e078e2d3b5d7ba5a6159e650945153262b44b76f6700f8e9edb261c5143e  LICENSE

package/libpng/libpng.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-LIBPNG_VERSION = 1.6.42
+LIBPNG_VERSION = 1.6.43
 LIBPNG_SERIES = 16
 LIBPNG_SOURCE = libpng-$(LIBPNG_VERSION).tar.xz
 LIBPNG_SITE = http://downloads.sourceforge.net/project/libpng/libpng$(LIBPNG_SERIES)/$(LIBPNG_VERSION)