Bump x509-limbo and/or wycheproof in CI (#13178)

Co-authored-by: pyca-boringbot[bot] <pyca-boringbot[bot][email protected]>

Author: pyca-boringbot[bot]

.github/actions/fetch-vectors/action.yml

@@ -16,5 +16,5 @@ runs:
       with:
         repository: "C2SP/x509-limbo"
         path: "x509-limbo"
-        # Latest commit on the x509-limbo main branch, as of Jul 10, 2025.
-        ref: "7eab84f30b70b5e940c211f47d53811545bda252" # x509-limbo-ref
+        # Latest commit on the x509-limbo main branch, as of Jul 16, 2025.
+        ref: "2a9d7f289d1c2bb5f9cbc565c529df933a35679e" # x509-limbo-ref