v0.6.1 release

Minor release

core

• fix version number
• zlib or zlib-ng are now required

CI

• update action for windows
• replace openFPGALoader-Documentation subdir with a tarball

files

• add zlib-ng as possible decompress library if zlib not found.

Contributors

• Jean THOMAS (@jeanthom)
• Unai Martinez-Corral (@umarcor)