fix(build): upgrade twine to >=7.0.0 to support Metadata-Version 2.5 (#1100)

## Problem
The `Run twine check` CI step fails on all PRs (e.g. run
[31887608422](https://github.com/testcontainers/testcontainers-python/actions/runs/31887608422/job/95019090461?pr=1090)
on #1090) with:

```
Checking dist/testcontainers-4.15.0-py3-none-any.whl: ERROR InvalidDistribution: Invalid distribution metadata: '2.5' is not a valid metadata version
```

Root cause and original tracking issue: #1096.

## Fix
`hatchling` emits `Metadata-Version: 2.5` in built wheel/sdist metadata.
Rather than pinning `hatchling` back to an older version (as done in
#1095), this upgrades `twine` to `>=7.0.0`, which officially added
support for Metadata-Version 2.5, fixing the root cause instead of
working around it.

Supersedes #1095 as the preferred fix.

## Verification
Ran locally:
```
uv build && uv run twine check dist/*
```
Wheel METADATA shows `Metadata-Version: 2.5` (hatchling unpinned), and
both wheel and sdist pass `twine check` (`PASSED`).

Author: Tranquility2

pyproject.toml

@@ -134,7 +134,7 @@ test = [
   "sqlalchemy-cockroachdb>=2",
   "sqlalchemy-cratedb",
   "paramiko>=4",
-  "twine>=6.2.0",
+  "twine>=7.0.0",
   "anyio>=4",
   "tomli>=2.0; python_version < '3.11'", # required for pyproject.toml tests, TODO: remove once we drop py3.10 support
   "pytest-xdist>=3.8.0",