fix(generator): handle list-typed nullable fields from upstream spec

[natalie-o-perret]

The upstream Exoscale OpenAPI v2 spec now emits type as a list
for nullable fields, e.g. "type": ["integer", "null"]. The code
generator at generator.py:74 assumed type is always a str,
causing TypeError: unhashable type: list`` on import.

Before (master): pytest collects 0 items, 2 errors

tests/test_client.py ▸ exoscale/api/v2.py:97 ▸ generator.py:74
  typ = _type_translations[item["type"]]
TypeError: cannot use "list" as a dict key (unhashable type: "list")

After (fix):

collected 16 items
tests/test_client.py ........                                        [ 50%]
tests/test_partner_client.py ........                                [100%]
============================== 16 passed in 0.08s ==============================

Changes:

• Added _translate_type() helper in generator.py that handles both
  str and list type values (list → "int | None")
• Replaced all 7 direct _type_translations[<expr>] call sites with
  _translate_type(<expr>)
• Added uv run pytest step to openapi.yaml auto-update workflow so
  spec changes are verified before committing to master

Note

AI-assisted for initial investigation and implementation.