gh-139330: Check expat version/checksum in SBOM with refresh.sh

Check expat version/checksum in SBOM with refresh.sh
(cherry picked from commit 89b5571)

Co-authored-by: Seth Michael Larson <[email protected]>

Author: sethmlarson

Misc/NEWS.d/next/Tools-Demos/2025-09-25-10-31-02.gh-issue-139330.5WWkY0.rst

@@ -0,0 +1,3 @@
+SBOM generation tool didn't cross-check the version and checksum values
+against the ``Modules/expat/refresh.sh`` script, leading to the values
+becoming out-of-date during routine updates.

Misc/sbom.spdx.json

@@ -224,14 +224,14 @@ def check_sbom_packages(sbom_data: dict[str, typing.Any]) -> None:
             )
 
         # libexpat specifies its expected rev in a refresh script.
-        if package["name"] == "libexpat":
+        if package["name"] == "expat":
             libexpat_refresh_sh = (CPYTHON_ROOT_DIR / "Modules/expat/refresh.sh").read_text()
             libexpat_expected_version_match = re.search(
                 r"expected_libexpat_version=\"([0-9]+\.[0-9]+\.[0-9]+)\"",
                 libexpat_refresh_sh
             )
             libexpat_expected_sha256_match = re.search(
-                r"expected_libexpat_sha256=\"[a-f0-9]{40}\"",
+                r"expected_libexpat_sha256=\"([a-f0-9]{64})\"",
                 libexpat_refresh_sh
             )
             libexpat_expected_version = libexpat_expected_version_match and libexpat_expected_version_match.group(1)