Release candidate: 8.0.0-rc2

[jtv]

I just released the second release candidate for 8.0.0. This is a big release and I'm having some health problems that force me to move slowly and carefully, so we're doing release candidates now.

Please try it out and let me know how it goes!

Changes from RC1:

• Add begin() const, end() const, etc. to pqxx::array.
• Cursor close() is no longer noexcept. Destructor still is though.
• Fix to make pqxx::array streamable.
• pqxx::zview now asserts the terminating zero.

There are also a few tweaks to the internals, particularly in encoding support and in streaming. Things got a little bit simpler, and hopefully a bit faster as well. I've added a few assertions though, so please let me know if any of those fail.

You can follow the work and see the diffs in PR #914.

[jtv]

This discussion has been superseded by the one for RC3. Thanks to those who tested, debugged, complained & contributed!