v0.3.3

A faster Python package. No library code changed, and every input parses
to what it did in 0.3.2.

Changed

• The Python package spends far less of each call in Python: parse
  takes a quarter to a third of the time it did (3.5 µs to 1.1 on Python
  3.13, in docs/PERF.md), Parser.parse about half, and Layout.parse
  and detect a half to two thirds, with the same answers. From Python,
  parse is now faster than strptime given the format. The
  default options go to the library as NULL and other options are built
  once and shared; a result's fields are read in one struct unpack, its
  Time and Result built without the dataclass __init__, and its
  layout is a view of the result rather than a copy. A failed call is
  run again with diagnostics, for its message, so a parse that succeeds
  never pays for them.