### What does this PR do?
Update `rules_python` from version 1.6.3 to 1.8.3 with the aim at reducing the number of warnings seen in CI, which tend to indicate an underlying combinatorial explosion when looking for Python wheels.

### Motivation
Some CI runs generate thousands of warnings like:
```
DEBUG: rules_python:pypi:create_whl_repos WARNING: Could not find a whl or an sdist with sha256=...
```
([example](https://gitlab.ddbuild.io/DataDog/datadog-agent/-/jobs/1406186495)).

While switching to version 1.8.x alone is unlikely to eliminate all warnings, it brings changes that should help reduce their frequency:
- bazel-contrib/rules_python#3225
- bazel-contrib/rules_python#3385
- bazel-contrib/rules_python#3441
- bazel-contrib/rules_python#3432
- bazel-contrib/rules_python#3447

### Describe how you validated your changes
For that, I'll be monitoring logs once the change is merged to the mainline, see why below.

### Additional Notes
Coming next:
- this is a mitigation/preparation step: if warning counts don't decrease significantly, the next step would be to add `target_platforms` to the `pip.parse()` configuration to explicitly limit platform checks, which is worth a dedicated PR,
- even if it's tiny, the patch on `rules_python` must be removed once bazel-contrib/rules_python#3579 is addressed. Without it, we used to face `ValueError`s which were preventing the version bump.

Co-authored-by: regis.desgroppes <regis.desgroppes@datadoghq.com>