fix(deps): give the three unbounded dependencies a lower bound

[lesnik512]

Closes #52.

tenacity, sqlalchemy[asyncio] and asyncpg were each declared as a bare name, so the declared range admitted every release ever published. SQLAlchemy resolved to 0.1.0, released in 2006:

Failed to build `sqlalchemy==0.1.0`

The package did not install at its own declared minimum on any supported Python.

The floors

Each bisected against the suite, not guessed:

dependency	floor
tenacity	>=8.4.1
sqlalchemy[asyncio]	>=2.0.18, marked >=2.0.31 on 3.13+
asyncpg	>=0.28, marked >=0.30 on 3.13 and >=0.31 on 3.14+

Two need marking per interpreter, both found by verifying the bisected floors on every supported Python rather than only the oldest:

• SQLAlchemy below 2.0.31 fails its own TypingOnly check at import on 3.13+, against the __static_attributes__ and __firstlineno__ attributes Python 3.13 added.
• asyncpg declares requires-python >=3.8 on every release but ships no cp313 wheel before 0.30 and no cp314 wheel before 0.31, so a resolver picks an sdist that cannot build rather than reporting a conflict.

Marked rather than raised outright, since 2.0.18 and 0.28 are genuinely fine on 3.11 and 3.12. Same shape as modern-python/faststream-outbox#186.

Verification

uv pip install --resolution lowest-direct . then the full suite against Postgres 17:

interpreter	result
3.11	40 passed
3.12	40 passed
3.13	40 passed
3.14	40 passed

just lint-ci clean. Normal resolution: 40 passed.

Nothing changes at the top of the range, so this is inert for anyone not installing at the lower bound.