Define wheel version via file/target

# 🚀 feature request

### Relevant Rules

* py_wheel

### Description

I would like use wheel version generated by other target.

### Describe the solution you'd like

```

my_version_generator(
name = "version"
...
)

py_wheel(
name = "foo",
version_file = ":version",
...
)
```

Solution should be a bit similiar to https://github.com/vaticle/bazel-distribution/blob/ebb4a9b342ec442c427705ec6a7919cce4c35c6e/maven/rules.bzl#L258

### Describe alternatives you've considered

* Generating version before build and passing via variable in volatile status. Solution is inconvenient for multiple modules and is against bazel design.

Start by locating the py_wheel rule and reviewing how its current version is configured. Compare the requested version_file target behavior with the linked maven/rules.bzl example; done means a generated target can provide the wheel version, including support for multiple modules.

Scritto dal modello di indicizzazione a partire dal testo della issue.