fix external libigl md5

Author: alemuntoni

src/external/libigl.cmake

@@ -14,7 +14,7 @@ if(MESHLAB_ALLOW_DOWNLOAD_SOURCE_LIBIGL)
 		set(LIBIGL_LINK
 			https://github.com/libigl/libigl/archive/refs/tags/v${LIBIGL_VER}.zip
 			https://www.meshlab.net/data/libs/libigl-${LIBIGL_VER}.zip)
-		set(LIBIGL_MD5 0b4fea5dba2117b8db85c99a39a71f83)
+		set(LIBIGL_MD5 b5f95849d6828fd1f41b7aff1a55f4b0)
 		download_and_unzip(
 			NAME "LibIGL"
 			LINK ${LIBIGL_LINK}