fix: bound 429 retry_after and retry connection errors without a proxy (v0.1.5)

A server-controlled 429 retry_after/Retry-After was slept verbatim with no
finiteness check or ceiling, so an inf or huge value (adversarial or a
ms-vs-s unit mismatch) could stall send() for hours outside max_retries
accounting. Non-finite values are now rejected and finite values clamped
to MAX_RETRY_AFTER (300s).

Connection/timeout errors with no proxy provider set failed one-shot,
contradicting the README's documented "normal retry" behavior and skipping
the single most retry-worthy failure class. They now raise the internal
_Retryable signal so commons.aretry retries them under max_retries, same
as a 5xx, while still returning a failed WebhookResult (never raising)
once retries are exhausted.

Signed-off-by: disqualifier <dev@disqualifier.me>

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "aiowebhooks"
-version = "0.1.4"
+version = "0.1.5"
 description = "async webhook sender (aiohttp) with round-robin urls, retry, and proxy rotation; optional discord.py embeds"
 requires-python = ">=3.10"
 dependencies = [