`configure` expects Python 3.15 on `main` after `3.16.0a0` cut

[brettcannon]

Bug report

Bug description:

cpython/configure

Line 607 in f5c7535

PACKAGE_VERSION='3.15'

It looks like as part of the cut over to 3.16, configure wasn't regenerated with 3.16 itself. This shows up in cross-builds and was detected thanks to the WASI buildbot suddenly failing.

CPython versions tested on:

CPython main branch

Operating systems tested on:

Other

[brettcannon]

#149500 would fix this.