This adds Python 3.9 and 3.10 typing syntax to files that import
attributions from __future___. Python 3.9 should be able to cope with
the 3.10 syntax, but Python 3.8 will no longer work.
On Windows/Mac, install the latest Python 3.9 version from python.org.
There are currently no orjson wheels for Python 3.10 on Windows/Mac,
which will break the build unless you have Rust installed separately.
On Linux, modern distros should have Python 3.9 available already. If
you're on an older distro, you'll need to build Python from source first.
We no longer need to worry about pysqlite implicitly beginning
transactions, and can be more explicit about beginning/ending
transactions
save() now also has a trx argument controlling whether a
transaction should be started / left open
