make async with < 3.10 compatible

[jacobbednarz]

With the commit builder, the SDK uses parenthesized async with syntax.
Example:

async with (
      httpx.AsyncClient() as client,
      client.stream(...) as response,
  ):

This syntax is only valid in Python 3.10+. However, pyproject.toml
declared requires-python >= 3.9.

So on Python 3.9, the entire commit module would fail to
import with a SyntaxError at startup making it completely unusable
despite the package claiming 3.9 support.

Updating this syntax allows it to be compatible all the way back to 3.1.

---

Alternatively, if we'd rather push 3.10+ we can also update the
pyproject.toml to reflect that instead.

[jacobbednarz]

i suspect this break came from the ruff check

$ uv run ruff check pierre_storage

SIM117 [*] Use a single `with` statement with multiple contexts instead of nested `with` statements
   --> pierre_storage/commit.py:392:9
    |
390 |           }
391 |
392 | /         async with httpx.AsyncClient() as client:
393 | |             async with client.stream(
394 | |                 "POST",
395 | |                 self.url,
396 | |                 headers=headers,
397 | |                 content=self._build_request_body(metadata),
398 | |                 timeout=180.0,
399 | |             ) as response:
    | |__________________________^
400 |                   if not response.is_success:
401 |                       error_info = await _parse_commit_error(response, "createCommit")
    |
help: Combine `with` statements

SIM117 [*] Use a single `with` statement with multiple contexts instead of nested `with` statements
   --> pierre_storage/commit.py:492:5
    |
490 |       url = f"{base_url.rstrip('/')}/api/v{api_version}/repos/diff-commit"
491 |
492 | /     async with httpx.AsyncClient() as client:
493 | |         async with client.stream(
494 | |             "POST",
495 | |             url,
496 | |             headers=headers,
497 | |             content=request_stream(),
498 | |             timeout=180.0,
499 | |         ) as response:
    | |______________________^
500 |               if not response.is_success:
501 |                   error_info = await _parse_commit_error(response, "createCommitFromDiff")
    |
help: Combine `with` statements

Found 2 errors.
[*] 2 fixable with the `--fix` option.

will see what we have do do in order to prevent regressing again.

[imownbey]

Assuming it’s backwards compatible with the old sdk methods sounds fire