Allow more array types for SQLite

[dantownsend]

The way we store arrays in SQLite is by converting the values to JSON strings, and then storing them in a text field.

We have this function which converts list values into JSON:

piccolo/piccolo/engine/sqlite.py

Lines 84 to 91 in 0e2ec8a

	def convert_array_in(value: list):
	"""
	Converts a list value into a string.
	"""
	if value and type(value[0]) not in [str, int, float, list]:
	raise ValueError("Can only serialise str, int, float, and list.")
	return dump_json(value)

We validate the types here to make sure we can serialise it.

The list of types is fairly limited - it excludes Decimal, date, and datetime, because Python's json.dumps is pretty restrictive. We might be able to extend json.dumps to handle these additional types.

Note - if orjson is installed, this is less of a problem, as it serialises far more types.

[sinisaos]

Date / Time / Timestamp / Timestamptz is supported in SQLite since Piccolo v.1.7.0. Decimal (Numeric) remains unresolved, but I made a small PR that fixes it.