pngcheck-2.3.0-bp151.4.3.1

- security update
- added patches
  fix CVE-2020-27818 [bsc#1179528], global buffer overflow was discovered in check_chunk_name function via crafted pngfile
  + pngcheck-CVE-2020-27818.patch

- Use url for source
- Cleanup spec file with spec-cleaner

- micro spec file cleanup, created *.changes

- created 2.3.0