Fix downloads hanging after completion
Downloading a package could hang after all data had been received, leaving ponyup stuck until killed.
Fix downloads failing on macOS
On macOS, downloading a package could fail when connecting to a host that resolves to more than one address. Cloudsmith, where ponyup downloads packages from, is one such host. Linux and Windows were not affected.
Fix HTTPS downloads silently losing data or failing
Several bugs in HTTPS connection handling could cause downloads to fail, data to be silently dropped, or one connection's failure to break a different connection. These could show up as unexplained download failures or checksum mismatches.