Upgrade libpng to 1.6.57 for CVE-2026-34757#16597

Kanishk-Bansal wants to merge 1 commit intofasttrack/2.0microsoft/azurelinux:fasttrack/2.0from

cblmargh/libpng-upgrade-to-1.6.57-fasttrack/2.0microsoft/azurelinux:cblmargh/libpng-upgrade-to-1.6.57-fasttrack/2.0Copy head branch name to clipboard