Support `.bzl.<N>` suffixes for pybind11_bazel versions.

python_configure.bzl

diff --git a/python_configure.bzl b/python_configure.bzl
index 4f2c0f9..8994a22 100644
--- a/python_configure.bzl
+++ b/python_configure.bzl
@@ -475,6 +475,9 @@
         )
 
     version = _parse_my_own_version_from_module_dot_bazel(ctx)
+    # The pybind11_bazel version should typically just be the pybind11 version,
+    # but can end with ".bzl.<N>" if the Bazel plumbing was updated separately.
+    version = version.split(".bzl.")[0]
     http_archive(
         name = "pybind11",
         build_file = "//:pybind11.BUILD",