Hypothesmith

- Use the `lark` package on PyPI, for Lark version 1.0+ (requires recent Hypothesis)
- Use updated Python grammar for `from_grammar()`, thanks to Lark updates
- Drop support for Python 3.6, add 3.10 and 3.11 to CI

- More efficient generation of Python identifiers
- Workaround for [CPython parser bug in 3.9.8](https://bugs.python.org/issue45738) (#16)
Yes, *yet another* one - still, that's why `hypothesmith` exists...

- Fixed rare internal error when `from_node()` generated misplaced `except:` clauses

- Now compatible with Hypothesis 5.46 and later
- Increased diversity of examples generated by `from_node()`

- Adds a workaround for [BPO-42218](https://bugs.python.org/issue42218)
- Bumped Hypothesis requirement to version 5.41 or later (better internal error messages)
- Added `MANIFEST.in` so the sdist includes license, tests, etc.

- Improved error messages from internal compiler errors *again*
([BPO-42218](https://bugs.python.org/issue42218) will be fixed in Python 3.9.1)
- Bumped Hypothesis requirement to version 5.39 or later