Update of libpng to 1.6.53

Recent changes are:

• Changes from version 1.6.52 to version 1.6.53

• Fixed a build failure on RISC-V RVV caused by a misspelled intrinsic. (Contributed by Alexander Smorkalov.)

• Fixed a build failure with CMake 4.1 or newer, on Windows, when using Visual C++ without MASM installed. (Reported by Andrew Tribick; fixed by Luis Caro Campos.)

• Changes from version 1.6.51 to version 1.6.52

• Fixed CVE-2025-66293 (high severity): Out-of-bounds read in png_image_read_composite. (Reported by flyfish101 flyfish101@users.noreply.github.com.)

• Fixed the Paeth filter handling in the RISC-V RVV implementation. (Reported by Filip Wasil; fixed by Liang Junzhao.)

• Improved the performance of the RISC-V RVV implementation. (Contributed by Liang Junzhao.)

• Added allocation failure fuzzing to oss-fuzz. (Contributed by Philippe Antoine.)