Fix a regression in the GTK3 branch where ORA files could not be opened in older Pinta versions.
Fix a regression in the GTK3 branch where ORA files could not be opened in older Pinta versions.

This was caused by updated to the latest SharpZipLib version - see https://github.com/icsharpcode/SharpZipLib/issues/131.

Fixes: 1909780

PintaProject/Pinta,PintaProject/Pinta,PintaProject/Pinta