[libpng] Update to 1.6.56 (microsoft#50853)

Author: ajtribick

ports/libpng/portfile.cmake

@@ -12,7 +12,7 @@ if ("apng" IN_LIST FEATURES)
     vcpkg_download_distfile(LIBPNG_APNG_PATCH_ARCHIVE
         URLS "https://downloads.sourceforge.net/project/libpng-apng/libpng16/${VERSION}/${LIBPNG_APNG_PATCH_NAME}.gz"
         FILENAME "${LIBPNG_APNG_PATCH_NAME}.gz"
-        SHA512 2f85d3b7c6341245a56029f2dd8de6fd59f2950f9030ecb3f8b7c07ba753f3deb8345077aa167f3efe0628089818608e7e780415530a8ca51fa77fc256daaa74
+        SHA512 dbc1f1dbd5f056fba586ed62bb8a61aff74a3610acb67abfafa81cb381bdb74eb96d8cd14f248e122396105b1382209080de30f2ac02d6588fd6493f6e30b399
     )
     set(LIBPNG_APNG_PATCH_PATH "${CURRENT_BUILDTREES_DIR}/src/${LIBPNG_APNG_PATCH_NAME}")
     if (NOT EXISTS "${LIBPNG_APNG_PATCH_PATH}")
@@ -30,7 +30,7 @@ vcpkg_from_github(
     OUT_SOURCE_PATH SOURCE_PATH
     REPO pnggroup/libpng
     REF v${VERSION}
-    SHA512 98ce4acef95ab92ec03039fa0b60b229c0ca607bf1bbe4295f92c638940ecd2d03aba63186ee837b063c09f8176de4987853df96549436c90f588d69f9061a3c
+    SHA512 352ea0d78ae50c19ee2b99714f9a66773ad18f22c18a5fb693481d9c87a372a6bf8cd7b3e7c482f2e0474ed80ddc337a2e8ec38d148212eb175d15ca0257c03a
     HEAD_REF master
     PATCHES
         "${LIBPNG_APNG_PATCH_PATH}"

ports/libpng/vcpkg.json

@@ -1,6 +1,6 @@
 {
   "name": "libpng",
-  "version": "1.6.55",
+  "version": "1.6.56",
   "description": "libpng is a library implementing an interface for reading and writing PNG (Portable Network Graphics) format files",
   "homepage": "https://github.com/pnggroup/libpng",
   "license": "libpng-2.0",

versions/baseline.json

@@ -5413,7 +5413,7 @@
       "port-version": 1
     },
     "libpng": {
-      "baseline": "1.6.55",
+      "baseline": "1.6.56",
       "port-version": 0
     },
     "libpopcnt": {

versions/l-/libpng.json

@@ -1,5 +1,10 @@
 {
   "versions": [
+    {
+      "git-tree": "8420c601b09fe9ea3fd8fa2d88d449d6e47660ae",
+      "version": "1.6.56",
+      "port-version": 0
+    },
     {
       "git-tree": "f300cf728bdcc0e998f18a520467cfdae5667bdf",
       "version": "1.6.55",