Full support for the Session extension
Added Connection.setlk_timeout(), apsw.mapping_setlk_timeout_flags, and enabled the timeout for amalgamation builds such as PyPI.
Shell open command allows specifying flags to open a connection, and connection command shows flags used for each open. (APSW issue 557)
Type stubs updated to collections.abc.Buffer (Python 3.12+) wherever some bytes are taken. Buffers have always been used, but Python 3.12 added typing.