Use py_runtime_pair from rules_python

[iteratee]

py_runtime_pair was completely removed from bazel_tools with bazel 8. Using the version from rules_python should not cause problems for users of bazel 7 and earlier.

I haven't tested with earlier bazel versions. Depending on the supported range of bazel versions, I can test locally.

[avdv]

Thank you, that looks reasonable.

But CI failed with:

 ERROR: https://bcr.bazel.build/modules/rules_jvm_external/6.3/MODULE.bazel:101:13: name 'use_repo_rule' is not defined

We have to use an older rules_python version which is still compatible with Bazel 6.x.

Oh, and in WORKSPACE mode, rules_python is not even available:

The repository '@rules_python' could not be resolved: Repository '@rules_python' is not defined.

[iteratee]

I'll see what I can do. From my testing with rules_haskell, I wasn't able to get this change to work at all with bzlmod and bazel 6.

As they continue to diverge it will get harder to support more different major versions of bazel.