MGASA-2021-0210 Updated pngcheck packages fix a security vulnerability

This update fixes a divide-by-zero crash bug and probable vulnerability in interlaced images with extra compressed data beyond the nominal end of the image data. found by "chiba of topsec alpha lab" rhbz1949800...

MGASA-2020-0479 Updated pngcheck package fixes security vulnerability

Multiple buffer overflow flaws were found in pngcheck 2.4.0 and older rhbz1902806...