example: Add example for pybind11

[hofbi]

Add an example for pybind11 with rules_py which is a modified version of https://github.com/pybind/pybind11_bazel/tree/master/examples/basic.

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Changes are visible to end-users: no

Test plan

• New test cases added

[alexeagle]

Thanks! but it doesn't appear this is being tested by our CI. We also don't have sub-modules in the other examples folders. Could you move the new dependency to the root MODULE.bazel (with dev_dependency=True) and verify this is getting tested?

[hofbi]

Can do.

Isn't the UV example I am bumping in #374 a submodule?